1. Between 2 and 3 ounces for me. I use any leftovers on other stuff, but I hate to run out.
2. Depends on your base,etc... More for flakes or to cover tape lines from artwork, only a couple for regular basecoat. My goal is usually to have enough in the first session to make sure I can get rid of any runs/sags/dust nibs etc... without harming the base coat. I don't always have these things but when I skip a little they always pop up where I didn't see them.
-I usually work in at least 2 sessions. The first I lay down clear and sand it back with about 600. The second I aim for one flowing coat to "flo coat" much less buffing etc... that way. For flakes I might do 3.
3. Flash times vary on location.(temp/humidity/air flow etc...) The tech sheets will tell you how to test and give you a general idea.
4. Lacquer thinner is my choice.