As a model painter I think you are doing a great job, it does take skill to tape off a model correctly and you are correct in painting the light colors first, many times when painting yellow I will paint the model white first, yellow is a hard color to cover in thin coats, or use white primer depending on the model. I hope you plan to use a dullcoat clear finish coat, it makes the model just stand out and gives it the rich look. The blue color looks like about the correct sheen I would want. I will say one thing when you first posted this article I thought it was more work then you wanted to do, or could do, but you proved me wrong, your a pretty good modeler, most couldn't do what you are doing and get the results your getting. Here are two tractor sprinklers that my neighbor thru in the trash, bless his heart, he can't fix anything. Yes, that's John Deere green in the spray can, now there too nice to use.
trainman