Hiya Gregg,

My new post may be of interest as our layout sizes very similar. Try to avoid the interaction between the speaker and another suface close to it - this is far more of an issue than the heat (cabinets actually run quite cool, not like the older M3's etc.) I have stand mounted the fronts and omnimounted the centre. Is firing across rather than along an option? would give you better sound staging. If M33 close to side wall then toe in more to avoid tweeter reflections and thus timing / phase errors.

Im my system I have customised the Trifield - increase treble +0.5 (M33's rounded off, see review), increase width to 1.5 and changed depth to -1.5.

Also, buy a B&W PV1 sub ~ trust me - it works!

Good luck!