Rollers - Major resistance issue

Earlier on this year I dug out my Minoura 3" rollers. I had the band stretched around all three drums and understand this creates more resistance than around two. On saturdays I was doing low cadence big gear efforts and found that there was not enough resistance and couldnt keep my cadence down to 60rpm. Purchased a Minoura resistance unit its like a turbo bolted on my rollers. On the easiest setting my average speed has dropped from 17mph to 11mph with an average cadence of 82rpm. Spoke to Minoura they cant tell me how much resistance the set up is producing at speed and have not wanted to say much at all. I now have to use a 36T chainring last week I was using a 52T. Over the last four sessions I have found myself leaning on the wall and once recovered I start to pedal again. This is pretty much how I taught myself to use the rollers some years ago. In the past week I have not noticed any gains speed wise. I think I need to take off the resistance unit, my knees seem ok at present and I kinda like them where they are. I have purchased some earth magnets which are in the post and hope to use these for a little bit of resistance when required.

Is it likely that I will develop speed from persevering with my current roller set up?