Believe me, I've gone over it a million times on nearly all of my machines. My spray painter - who is going to paint the cabinet and has agreed to repair it, get it level and clear in between each coat has agreed to this no dramas. If it gets stuffed, easy fix. No such luck with a playfield. From reading and research generally its one thin coat, let it set, block it then at least another two or so thin coats as well. Given its not baked in the oven. He isn't keen on doing a playfield because of the risks.
I guess the thing is, as long as your careful laying down the mylar, you can get a nice shine on it without the risk.
Maybe you can get a junk playfield and use it as a test for both yourself and your spray painter? I did 2 junk playfields before I attempted my first CC. The number of coats is really a personal preference and depends largely on the condition of the playfield and the type of clear being sprayed.
