Congrats on the new system. Building up one piece at a time is a great way to go, and going with M50s over M22s gives you a lot more flexibility for large rooms in the future.

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