This is an "I-had-fifteen-minutes-to-spare-yesterday-and-fifteen-minutes-today" update.
Here is four coats of Krylon Covermaxx Satin Clear:
I actually ended up with 6 or 8 coats before I stopped, not out of necessity but because I had some dust spots and wanted to test a few cleaning methods before I installed the part. A few of the cleaning methods were unfavorable, and I lightly sanded with 1000 grit and laid down a few extra coats to get back to a consistent finish.
In case you want to mimic this satin clear trim process: do NOT spray your trim directly with rubbing alcohol, or windex, and do NOT wipe with a paper towel. The rubbing alcohol left the surface dry and misty and uneven, I assume because of the uneven drying times based on uneven application (the thin parts tend to mist off quickly). The windex just left it looking water spotted, and the paper towel left too many hairs. I'm not sure if any of this did actual damage, but to get back to square one I wiped with a tack cloth and laid down the extra coats.
After another day of curing, the finish feels durable when handled, and doesn't show fingerprints or spots at all. My cleaning method that yields reliable results is: blot with 1:10 diluted purple power using a microfiber cloth. Blot dry with a microfiber cloth. Blot liberally with 303 aerospace protectant. Wipe gently all in one direction so you don't pick up any hairs on the rough surface. It sounds like a lot of steps, but for how clean my interior stays, this is probably an every-three-months sort of exercise.
Following my own cleaning method, here's the installed part. This is exactly the finished look I was going for, so I'll proceed with the same method for all remaining trim.
Cheers!