Forgot to write, insist that he does any/all prep work that will save you time....and him money.
Clean and clean and clean.....engine/wheel wells/jams etc etc
Remove bumpers, grill, junk tires to paint,pull door panels etc etc.
Make him a "to do" list before he brings the car
Let him help with the taping, let him knock down the filler and you finish it, let him do the wiping and tacking?