Unless your car is a “bolt on” car, I really prefer to have them at least 2 days, that way I can tune/verify the cold start. It’s much better, easier doing it this way, as I’m alot more than 1 hour away LOL. I would rather inconvenience you, than leave you with a tune with a cold start/driveability issue, that you would either have to get someone else to fix, or wait on me coming back up there.
It’s your call of course. I can do MOST of the tune without having it overnight. I can take a SWAG at the cold start stuff, and hope for the best.