Because Adam is right now spending some vacations in Mexico...maybe I can reply you the questions if you don't mind. Adam paint all his models in from my workbench, and I always look to his models. I think that I learn something, but not enought!!!
1) He doens't use primer. The black shadows is the frist layer. But if you need a good, good rpimer, I recomend you 3: Tamiya Primer (grey), Citadel Primer (the best one) and/or Mr Surface 1200 diluted and applied with airbrush.
2)I am not totally sure about the second one, but..what I can tell you is that you can dilutedthe clossy coat (Tamiya X22) like other colors....using laquer thinner always. And also the same ratio than the paints. It must work for sure.
And now...go for the other 998 questions... I will print them and I will left them over Adams Keybord. He will have fun after his vacations!!! (Just kidding!!)
ALl the best