The winning answer? Overtravel screw.
100 flawless rounds at the range today - first few were the worst I've ever shot, flinching all over the place.
Also, now that I'm past that, I have to declare victory with the barrel bushing - accuracy and consistency with this gun are much improved.
Now, to finish checkering the front strap - oh, and a couple of holsters.
Thanks again to all those who've offered up suggestions. It's nice to be able to ask a question and not be reminded how stupid you are (I've got kids for that).
Lane