I can attest that an oil based paint marker (the one I have is called "Uni Paint") will work. We used them to mark screws on scope mounts for when they had to be taken on and off in the field. It held up pretty well as long as the surface was cleaned REALLY well. Acetone works well, but lots of other stuff will too.
I have some on a .22 revolver, it has been on there for years. Granted it doesn't get used much, but lasting ten years for just a paint marker ain't bad.
Likely the combo you are using, the three different paints? They don't bond to each other and so you have a weak layer that compromises the whole thing. Artists have the same problem with paintings sometimes, especially restorations.
Testors will come off too easy. I know, I've used it before. But the other fellow on here said it works for him, so I suspect it depends on which solvents you use to clean. Normally solvents will remove it much easier than if you just use CLP for everything. I expected the paint marker to come off too, but it held up pretty well. An epoxy based paint will work best though. An auto body shop might be a good place... If they are painting a red car, all you need is one drop. I'd let you do it if it were me (because I doubt it happens often, if ever).
I've seen the glow in the dark paint, I even bought a vial of it way back when. It didn't hold up well at all, didn't glow either. Useless. If you really need glowing sights, you can't beat tritium. I have them on almost all my pistols.
If you have a pistol that they don't sell tritium sights for, you can get the sights drilled and have the tritium installed. Can't recall who does this, I inquired years ago looking to get it done to a Beretta. The cost really wasn't much different from just getting a set of sights either.