Hello Mac!
Respect for not giving up!
I'd like to give you a tip for painting light colours, like the gray on your aircraft, but I also have problems with that myself. What works for me is the Tamiya white primer from the spray can. On top of that you can brush light colours much better and they go on best if the paint is flat. If you need it glossy, it's much easier to put a top coat of future or other gloss clear on top of a flat paint, than putting on glossy light colour.
Hope it helps, thanks for sharing and have a nice day
Paweł