Yikes!
Well, since you seem to really love the Studio 60s, I think you'd prefer the M22s over the M3s, since they aer similar sounding speakers, with the exception of bass output. (You will have a sub, right?)
As far as mounting them horizontally, I'd recommend not using cone points. The reason for this is that the the M22s, and all Axiom speakers, have a wedge-shaped cabinet. Putting them on cones would result in the speakers pointing slightly upward. If possible, I'd use a bracket and mount them on the wall. This would give you some flexibility in aiming them toward your sweet spot. One last piece of advice, if you must mout them horizontally, is to have that the tops of the M22s face each other, so the tweeters are closest to your ears.
At the request of my wife, I gave up my Paradigm Monitor 9s about 1.5 years ago and replaced them with M22s and an SVS sub. This combination far surpasses the sound I got from the Paradigms alone. With luck, you'll survive this ordeal.
