Nobody's perfect Walter, but you need to give yourself credit. The cars look great, and I can tell what they are, so you're ahead of the game!
What I did was take my camera, and a model, and just start shooting pics, and moving the adjustment switch. After each picture, I would switch it over to view, and study the picture, and take notes on which picture looked good until I adjusted the camera to take pics well with consistency. With a digital, it doesn't cost a thing to keep taking pictures, and deleting them, unlike 35mm cameras.
I think you did a great job on all the kits. My biggest thing is foil, and it looks like you got it down to a science!
Keep up the great work, I look forward to seeing more!!!