Good idea. As long as the receiver handles "phantom center" operation (routing center information to the mains if you tell receiver "no center speaker") that would work fine. The M60s can carry the center information very well, just don't put them TOO far apart.
If you need a wider "sweet spot" immediately then one option would be a single M2, then move it to the back for 6.1 when you get your VP150.
M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
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