Sorry Bill.
I just used the KlassKote clear over their colors, even over white. That avoided the quantity/limited life issue of 2K for me. Yes, there is a slight yellowing as cured (probably from the hardener) but unless you are going over white, I don't think you'll ever see it. I ran tests on two airplanes that I painted white. The first refinish job was specifically to do this experiment, so I base-coated with the white, then applied some Monokote numbers, then clear-coated only the wingtip with the numbers. This let me evaluate the contrast side by side. The slight tinting shows up in some lighting conditions more than others, which is likely what you noted and are trying to avoid. At certain reflecting angles (lower incident angles) you can't easily see the difference. I note that with an iphone 10 camera, it doesn't seem to pick up the difference at all, whether under outdoor light or indoor. Obviously, that is just a distraction as I tried to show the difference by taking a photo, and what really matters is what people actually see....
A comment one of my flying buddies who was a professional painter made has stuck with me. That white was one of the most difficult colors to match when painting cars because there are so many different hues, and everyone tweaks it to suit their taste. I can't knowledgeably comment on where in this range the KK white is, but it seems pretty neutral, not much blue and not much "warmth" added either.
I would note that the paint job on this sample plane is likely over 15 years old now. As far as I can tell, it hasn't "yellowed" more with age. Yellowing might be accelerated by prolonged UV exposure, but I didn't test for that. My race planes don't get out every month for practice any more. Aging would be a concern for any clearcoat.
I have put KK colors over different spraycan primers, usually the Rustoleum Auto Primer, with zero issues so far. I generally let the primer cure for a week or so, mostly because I don't like painting and it is slow work for me.
In the future, I will try not to review endless reports on turbine blade disposal issues, pending anti-dumping laws for turbine blades (Sweetwater, Texas?), and alternative disposal methods such as grinding up and burning the fiberglass/epoxy waste stream in cement manufacturing plants....prior to replying to a perfectly good question on Stunthanger.
Again, my apologies....