Is it too late to suggest something other than square (18x18) for the room dimensions ? IIRC the room would be large enough that the dominant room mode would be down at 30 Hz but it would still help a bit if you could get length and width to be different...

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