@expresstrain That’s good info. When folks talk about space from the wall they measure from the front of the speaker. So if you pull them out a smidge or so you should have 20”-24” if I’m understanding you correctly.
Will the shelf you use have the tweeter line up with your ears in your sitting position? This is crucial
Rega RS1s will fit - check out some reviews and threads. If you’re interested DM me - I have a pair I’m not using.