quick follow up to my minor gripe about the upper flipper garage shot: while the rail had a nice smooth curve to it, it was still prone of the post above the Rick target, almost 3/8" inch. Enough such that a ball could strike the end of the rail outright, which seems objectively wrong.
So I moved the end of the rail down so that its end is flush with the top of the post (Yes I had to self-tap a new hole for this, but the rail tab covers the old one so it's no big deal). WOW what a difference! Shot is much smoother with no rattles, and if/when it does fail there's no question that "I flubbed it that time". I make the shot more often than not now and scores immediately reflected that - now I just need to get better overall (damn magna-save timing is my nemesis. Er, Nimbus?)
It's great to not have "that nagging feeling that something is off" anymore. Weirdly, that feeling is too strange of a "gut nag" to put into words - even with 18months of everyone posting about their similar experiences here, you almost have to sense it for yourself. I'm glad there were enough hints and tips here to find the resolution.