A light coat of Duplicolor etch and then top coat with clear to seal?

I think this might be a new twist in the primer debate. I'm considering coating the inside of my empennage with a light coat of Dupli-color self etching primer and then sealing it with a quick top coat of Dupli-color clear.
I'm thinking that it would be an easy, light and relatively inexpensive way to prime and seal the inside - just the inside.

I've use Dupli-color on my RC planes with good results, it goes on thin and even.

I have spent hours looking at every conceivable primer option. I'm sure that epoxy primers are the best,I just don't want to mess with them.

I tried that on a piece of aluminum interior trim. A few months later and it was slightly yellow and cracking. Flakes off easily.

That's not good, I'm not sure what would cause that. I originally intended to use SW wash but I can't get it in CA