Bought a M9A3 as well and will be doing the same ( red dot and Comp ) . Saw the Berreta team open gun and it uses the rail for the mount and it sits fairly low , but you would have to remove the Red dot and mount to the remove the slide for cleaning . I don’t personally care for dovetail mounts and milling the slide is out , way too thin . A grip panel mount doesn’t look doable , because the slide release comes back pretty far ( which I like because I can easily hit it with my thumb and not change my grip ) . So it’s looking like a frame mount that unfortunately would sit high and look bulky but open sights would be usable and facilitate slide removal . Comp will be made out of 303 stainless . My usual slide mill and suppressor sights are out on this one . Open to suggestions if anybody has any . Thanks in advance.