While dissembling to instal a new trigger in my KC9, one of the grip screw bushings actually came out (looks like they aren't staked and this one didn't get enough LocTite), so funny this came up as I'm about to (involuntarily) go down the "screwing around with screw bushings" road. Despite best efforts to avoid it, I ended up marring the threads of the old bushing getting the screw out of it, so reassembly will have to wait until a Brownell's order gets here. I used tape to make do for a quick live fire test of the trigger instal today.
Trigger installation in the KC9 and my backup Kimber went well though. I went with flat 10-8s instead of the Harrison's recommended upthread because I decided to just replace both - even the 9mm was chafing my finger due to the hole for the overtravel screw. The KC9's trigger did require fitting in pretty much every way possible (frame fit, overtravel, grip safety interaction, pinching mags), but it was a good experience. So far I'm liking the triggers a lot - I put 200 rounds of .45 through the Kimber today and it solved my hot spot problems.
As a note, I do know, and do try, to not over-tighten grip screws. I either did it anyway on this one or the bushing was just that insecure.