Don't feel bad about recommending the M3/M50 line. I think you summarized the issues in choosing between M3/M50 and M22/M60 families extremely well.

Now I'm going back upstairs to listen to my M40s

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