Is my room OK for Magneplanar 3.6's

Try setting up the speakers using the 1/3 rule. If the length is 15' place the speakers 4' from front wall sit at 10' and leave 5' behind you.Changing any of these by a foot worked for me . This was learned from robert harleys "the complete guide to hifi" has worked wonders with my mags.If these are your first mags also place diffusers behind the speakers and listening position as well.And if you add a subwoofer place it right by your listening position.This setup of a subwoofer blends best usually.

If possible in a room that size without being in the way, you might try a less commonly advertised but highly effective (for best sound) alternate placement strategy for the Maggies for best results. That would be about 1/3 to 1/2 way or so into the room and only a foot or two from sidewalls. You have to play with exact placement within these parameters to get optimal bass results.

Otherwise they may work but not reach their full potential with the more conventional placement closer to the rear wall for bass re-enforcement in a smaller room like that.

I agree with Schipo. I tried to fit the much smaller MG12s in an 11X13 room and felt it was too small a space. They need room.

I tried 3.5s in a similarly sized space many years back and could never get them to behave properly.

Not even close. Go with the 1.6 or 1.7 instead