I have no experience, sorry.
But I would just like to say that it must be so disappointing for the owners when a beautiful brand new bike like the one above is creaking away after just one week. Really shoddy engineering and design. Such a pity.
I recently changed my Ultegra 50/34 to a Dura Ace 52/36 and I've had no problems at all, infact it's one of my best upgrades !
I also live in a very hilly area and it suits me better than the compact set up.
I had the day of work on Tuesday last week and with a couple of mates we did part of the TDF route, Huddersfield to Sheffield and as you know the includes Holme Moss and I climbed that OK.
Be careful, the Praxis conversion will not work in all frames. Specifically mentioned on the Praxis website is the 2014 Synapse, check out the link below.https://praxiscycles.com/wp-content/upl ... ConvBB.pdf