Shimano 105 5700 10spd - what are my rear cassette options? (And where to buy?!)

Hey BR crew,
I built my partners CR1 up with this groupset a few years (In 2014 I think) back, and at the time as she was a strong rider, and it had a compact up front, I fitted a nice and closely spaced 11-25 at the rear.
Time moves on, and she cycles less, and she now is in need of some smaller gears.
It's a boggo standard 105 RD, so I am fairly sure the most I can get away with is an 30T?
Now comes the joy of trying to firstly find a cassette that is either an 11-30 or 12-30, and then even more difficult finding one that is in stock.
I have found 11-28, but I just don't think that will make enough of a difference, I'd like to get her close to something around a 1:1 ratio, so 34/30 at least.
However, as this type of cassette appears to be as elusive as unicorns, would I be best to change the RD for a long cage, and whack an 11-34 on there, as these seem to be pretty readily available.
Opinions please - oh and if anyone has seen any of what I need in stock, that would also be appreciated.
CRC seem to have virtually nothing in stock - Tredz are a bit better, woolyhatshop have some stuff, and just about to check Merlin.
She's not really bothered about lightness etc, so if I did go new RD & new Cassette, would I be safe to go Tiagra for example?
Or should I look to get one of those RD extenders, that bolt into the fitment point, and then the RD bolts onto the adapter to drop it down lower - do they work ok, any recommended ones if so?
Trying to do it for not much cash really, as it isn't warranted.
I built my partners CR1 up with this groupset a few years (In 2014 I think) back, and at the time as she was a strong rider, and it had a compact up front, I fitted a nice and closely spaced 11-25 at the rear.
Time moves on, and she cycles less, and she now is in need of some smaller gears.
It's a boggo standard 105 RD, so I am fairly sure the most I can get away with is an 30T?
Now comes the joy of trying to firstly find a cassette that is either an 11-30 or 12-30, and then even more difficult finding one that is in stock.
I have found 11-28, but I just don't think that will make enough of a difference, I'd like to get her close to something around a 1:1 ratio, so 34/30 at least.
However, as this type of cassette appears to be as elusive as unicorns, would I be best to change the RD for a long cage, and whack an 11-34 on there, as these seem to be pretty readily available.
Opinions please - oh and if anyone has seen any of what I need in stock, that would also be appreciated.
CRC seem to have virtually nothing in stock - Tredz are a bit better, woolyhatshop have some stuff, and just about to check Merlin.
She's not really bothered about lightness etc, so if I did go new RD & new Cassette, would I be safe to go Tiagra for example?
Or should I look to get one of those RD extenders, that bolt into the fitment point, and then the RD bolts onto the adapter to drop it down lower - do they work ok, any recommended ones if so?
Trying to do it for not much cash really, as it isn't warranted.
Felt F70 05 (Turbo)
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18
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And possibly a SRAM 12-32 cassette for circa £45.
I know they will fit the freehub, but do they tend to shift as crisply, and any recommendation if I do go the SRAM route as to whether I should go Shimano or SRAM chain, as I will change that at the same time.
She's not a demon descender so won't miss that 11 tooth, and it will mean the gears are a little bit less gappy than the only Shimano option I can easily find which is an 11-34.
*I now have found an Shimano 11-32 in stock if need be.
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18
If you find an SRAM one that fits the ratios and you don't have to mess about with mechs and extenders do that
Also consider Miche and Ambrosio, you can order your own bespoke ratio cassettes (Miche) from The Cycle Clinic (Malcolm)
Re chain - KMC or SRAM.
And for cassettes, don't be afraid of going Tiagra - if you use the 105 locknut from your existing cassette you basically equalise the weight difference. They shift every bit as well and last every bit as long, and they are current range rather than 2 generations old so much easier to get hold of.
I suspect a smaller cog at the front won't be required, she does have a winter bike that has smaller cogs, so that should cover than aspect, and she is pretty strong, just doesn't cover as many miles as she used to.
I'm tempted by the 11-34, but I can't help but feel (Seeing as I hate 11-32 ones due to gaps) that it will be really knock her out of her cadence rhythym with the mahoosive gaps.
If they made a 12-34 I would probably accept that as a compromise, but I don't think that exists as stock fitment.
Her current smallest gear is 1.36, with a 32 it will drop to 1.06, which I suspect which is about a 25% difference, not insignificant on the hills.
I was totally looking at Tiagra, but stock was low, though I did manage to find 11-34 in supply, and one place with an 11-32 - based on the above recommendations though I am erring towards then SRAM to get the 12-32 option, PBK have it for about £45.
I've just has a look at the RD, and have gotten a bit lucky, as it's a 5701 which t'internet tells me will accept up to a 30T - so might I be worth chancing my arm with the B tension screw, or should I just order one of those extender thingies?
Suppose the advantage with the latter is that I would then definitely be able to slot in a 34 should it be needed.
Have always liked the custom cassette ratio idea, but I think it's a bit overkill for the usage this will get although perhaps if she can get up hills more easily, it will encourage her to use it more!
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18
Just found a 10spd chain in stock, so should be good to go by mid week.
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18
I don't understand.
It gives you all the ratios you want at basically the same price as a cassette with ratios you don't want.
I don't understand
Still have the original shifters in stock as spares, probably worth a small fortune now!
Though the brakes are going on my upcoming TT bike build. Ah I had assumed a custom cassette was going to work out fairly pricey, my mistake - had also looked at Miche cassettes before, and opinion seemed to be very divided as to how well it shifted.
Having said all that, and even if they are not pricey, I think a 12-32 is what I was after, and that is what the SRAM one is, probably for a very similar price.
And just seen tis on his site:
"With miche start sprocket are 11t to 16t and finish sprockets 21t to 32t and 34t for shimano 11 speed. "
So no 34T option for 10 spd, so it would have been a custom specced 12-32 :-)
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18
Felt Z6 2012
Red Arthur Caygill steel frame
Tall....
www.seewildlife.co.uk
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18
Just now I get a 'sorry your order is cancelled' e-mail
Ordered a Tiagra 11-32 from elsewhere for £27 instead, so £20 saved.
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18
Removed wheel gave bike a good clean, included getting rid of any gunk on the jockey wheels - she doesn't wash it very often if at all :-(
Lockring removed, cassette a little bit reluctant to leave the freehub, but got it off with some gentle persuasion - guess it has been on there for about 7 years, though not many miles, teeth still look in good condition.
Removed the chain from bike.
New cassette installed, no spacers needed, all tightened up - put wheel back on the bike.
Tried the shifting out sans chain, and the jockey wheels are making contact on the 28, and clearly the 32 - as expected I guess, as I am fairly sure its an SS.
I ran out of time at that point, so will tackle fitting the chain another day, but I have a question.
The way I found of sorting chain length is to ignore the RD, and loop the chain around the biggest cog at both the front and the rear, and then add 2 links, that seems reliable, and I've never had any issues.
However, I am a tad concerned about doing that in this instance, as if the B screw is not sufficient to make it clear the 32, I will need to bring into play the RD extender I bought, I forget the make, but like a dog fang or something like that, which effectively makes the RD a long cage.
However if I have to do that, do we think the chain would then need to be longer?
I'm also not sure if it's a fair test to just try and wind the B screw in as fas as it will go, or even remove it as mentioned above, and invert, or whether with the chain fitted this would also affect where the jockey wheels sit, and may combined with the B screw be sufficient.
I know it's not an expensive part, but it would majorly pee me off if I made it too short and then had to buy another one - no other 10 spd bikes in our house, so can't easily be re-purposed.
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18