Speaker Positioning

Antonio:
A friend has Magnepan's 3.6 and had to deal with glass behind his speakers. After testing with different options we opted for using absorbing panels and vertical blinds. At the end the result was surprisingly good since he can balance the absorption amount to avoid too much taking into acount the other treatments in the room.
Drastic difference between fully open and closed blinds. Nice fine tunig tweak BTW. Luis

You did not mention how far from the side walls they are or if you treat the first order reflection points. If the speaker is not to bright facing you then do that. What you could do is face them straight ahead and slowely toe in until the center fill image is as tight/small as you can make it (realistic) then stop.

My suggestion, to aleviate the reflection problems, is to set your speakers and listening position on the the diagonal . Put your chair in one corner facing the opposite corner. Then set your speakers up in that same diagonal between your listening position and the corner that it faces . It will 'fix' quite a few problems and is easy and cheap to try ! Then set up your speaker toe-in or toe-out as you see fit.