If this guy works in a shack behind a used car lot, he's a quickie bodywork dude- I've seen what goes on in those shacks and it ain't right. I'm afraid you'll be sorely disappointed with his work.
If you do the bodywork right, you'll know it's right. Maybe you can bring him the prepped, stripped vehicle, and some quality materials and let him shoot it. My gut tells me to not let him touch the bodywork.
There's nothing wrong with shooting in a carport, either, if you pick the right day and time.
An old buddy of mine had a Cuda back in the day and paid one of these guys to "restore" it for him. When he got it back, it looked perfect-perfect
. About a year later the paint started flaking off the rear quarters and what do you think was underneath it? There was gallons and gallons of bondo there.
At that point, he started to network to find someone to do it right, and started to save some money, but he lent the car to his cousin, who used it to move a couple hundred pounds of marijuana across state lines, and the feds impounded the car and he never got it back.