I've noticed the same issue with Kimber slide stops, both the crap that comes stock on them and the fact the the slide release notch is too wide. Unfortunately I don't know of any vendors that offer one with a longer release tab. As for the dimple, oddly enough I had the same slide-lock problem on my Remington Rand last time at the range. Afterward I put a slight dimple on the back of the slide stop using my Dremel and the thing actually behaves now. I consider that dimple just as mandatory on a defensive 1911 as good sights and a polished feed ramp.