In fact I put mine up yesterday. There are holes at the top of the speakers 11 inches apart.
So I measured 12 inches down, 15 inche in, drew a stright line across using the ceiling as my plum line to keep things straight and then drilled two holes eleven inches apart, fitted raw plugs put in the screws and then hung those babies up opposite each other firing across the listening position.
I have full victorian coving in my lounge so the rear wire is routed on that, out of sight and down the wall rather than up.
Looks good, sounds great..
Captain B.