For the sealer, basecoat and clearcoat I will be using all PPG products.
I will use PPG's DP90LF epoxy primer sealer. Then PPG Omni basecoat. And then we will follow it up with PPG's DC4000 clearcoat.
i am not questioning you with my comments. you know what you are doing. i have been lightly following your build on IMBOC. i was scrolling down and saw this thread in the main board.
you might want to think about using a better sealer. epoxy thinned out as a sealer tends to shrink after a few weeks. that's the chemical nature of epoxy. it starts out as a thermo-plastic product for the first 2 weeks. after the first 2 weeks it becomes a thermo-set product. during this transfer it will shrink giving your smooth paint some texture. this might be a good thing, because a smooth paint job with some light texture is almost impossible to do.
i have been using PPG epoxy since the 80's and have seen this happen a LOT.
i myself use the envirobase ECS sealer line now. this is hands down the best sealer i have ever used. the biggest problem with it is it must be sprayed with a really good spray gun due to the high solids of the product. and you shouldn't spray it over bare metal. i give bare spots a little spray with SXA 1031.
your choice of the 4000 clear coat is a good one. this is a high solid clear that holds a shine and is extremely durable. it is also bakes well.
i use EC 530, fast cure, and 550, slow cure, clear coat. management doesn't want to stock 2 different catalysts for the 2000, fast, and 4000, slow, clears or this is what i would use.