Most likely you will not be able to prevent the mounting finger from rotating in that adapter. Even if you initially have some success, the tab that acts against rotation will soon shear off. Maybe the design could have worked if these units were made to a higher precision, but they are not.
That clamp has already arrived and I see your point about the anti-rotation tab being flimsy but it's probably only there to keep things in alignment while the bolt is tightened. My current objective is to confirm that I can get the front derailleur to work. I can then get a better clamp.
Originally Posted by
Jipe
I listed Ridea and Color+ which are high end expensive brands as examples but there are cheaper types from Litepro for instance available on Aliexpress.
Thanks.
I've been occupied by the search for the other components. The Shimano FD-5700 appears to be the only front derailleur which is designed to acommodate a maximum chainring size of 56T (it's rated at 56T although I'm planning 54T - other derailleurs are designed for 53T or smaller) and my proposed shifter is a Shimano RS31 Revo twist shifter (old design but new stock) which isn't indexed and thus avoids the issue of compatibility with the FD-5700.