I have a Bushmaster Predator flat top with a Nikon 3-9x40 scope which should be good for a few hundred yards. Problem is, I'd like something for CQC as well, as this will also be used for HD. Should I be looking at reflex, holographic, red dot? The issue is, there is no room left on the rail except between the ring mounts. I was thinking of a mounting block that positions the optic at 1 o'clock and mounting a compact optic. I'm just not sure if this will interfere with case ejection. I don't want a bunch of multi level rails cluttering things up. Any thoughts?