Thanks, Dan. That was really useful.

One interesting question about the surrounds -- how did the levels you were testing at compare to the SPLs you normally get from the surrounds in a typical movie ? I'm wondering if the QS4s might turn out to be just fine as surrounds even though they couldn't handle the SPLs as mains ?

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