Sorry dude, I do this for a living; non catalyzed enamel based paints are not gonna last not matter what. I have seen it many many times.
The only way to get a good paint job is to have proper prep (we also don't typically use high build primers because we actually do proper metal/filler work and high build primers shrink too much leaving sanding scratches) and use good materials. Now I am not saying you have to use $1000 a gallon materials in fact at the restoration/collision shop we use $150 a gallon clear (including hardener) regularly with great results.
Stuff like this may work fine for a home hobbyist (where it doesn't have to be perfect) but not in the real world. We can't have people coming back because we used bad paint.
