Tried the Goof Off first. As I feared it might, it cut right through every layer at once. I gained some practice in spot repairs... practice I'd need later in the evening's work session...
...when I realized that what looked like shadows in the aft area was actually black overspray that misted down on the rear portion of the canopy top, beyond the masking paper! (If only I'd tossed a drop cloth over the unmasked portions of my work piece that I assumed were out of the range of the spray can
) I set to work trying to do something about the "tan lines" I had just discovered <<in retrospect, clearly visible in the middle photo of my previous post>>. I knew (by now) better than to touch them with solvent of any kind. Dry rubbing with paper towels took about half of it off, and blended the transition lines somewhat between overspray and pristine areas. I thought maybe a paper towel wet with water would do a better job.
That's where I discovered that I had already rubbed through the matte clear enamel topcoat in these areas and made a second discovery: the black specks in the stone texture spray paint layer are water-soluble (this is why you aren't supposed to use this paint for outside projects without a protective clear coat). Carbon black smudges appeared everywhere. There was nothing else to do but carefully rub these areas down to the gray latex layer and reapply the stone paint and clear coat. Thankfully this was easier to blend in than I feared, and I'm happy enough with the result that I'm stepping back and leaving well enough alone. It's overhead and behind the passengers' heads, an area not seen except when loading the baggage area or judging a show plane, which this isn't.
I share this saga in the interest of full disclosure regarding the faux Zolatone process. It is inexpensive and easy, looks good when done right, and I believe it will withstand light use and careful cleaning of spills should they occur. It does NOT wear like nails (i.e. like real Zolatone would) and it's easy to screw up. I'd paint my window trim (or fabricate removable trim rings) first, before I did the faux finish. Easier to mask in that sequence and harder to mess up what's already done. I think if you baby this stuff it will serve well in non-traffic applications. It's not my recommendation for foot and hand traffic areas. Repairs don't appear complicated, except let's face it - if you have to fix this finish once the cabin top is installed, you're no longer working on the bench, but overhead, inside your (possibly otherwise-finished) plane. I hope never to go there.
Last night's experience does make me optimistic about the results I'll see when I have to blend the paint work I've already done inside the top with the paint that will go over the epoxy-micro that's going to fair the top into the fuselage sides around the door openings. I anticipate that the transitions between those two paint jobs will be hard to detect visually.
Do I wish I'd finished my top in shiny urethane that wears like iron but shows every surface imperfection? Tough call. I am having second thoughts. After making the front page with nice-looking photos, all I can do at this point is fully disclose how it's going. Each builder will have to decide whether they want to try this approach.