>>???

If you find that the M3s sound better when the stands are pulled out a foot or so from the wall you will want to leave them there and not put them back on the ledge, right ? That will probably make your wife unhappy, which indirectly will make you unhappy.

You need to do something sufficiently nice for your wife that she doesn't mind you putting your speakers "right in the middle of the floor"

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8