I asked b/c I've been considered getting a spot welder for sheet metal. Right now I have a bunch of G90 sheet metal. If I continue to play around, I'll probably continue with G90 unless painting, etc. and then maybe just uncoated steel.
The turn in your answer was not about spot welding galv sheet metal BUT rather my understanding of you making a food grill to consume product off of it. I would assume you would spend significant time around the grill while it is tox'ing off zinc etc., and you are breathing that and flavoring your meal.
I also wouldn't bother making repetitive fires in a sheet metal grill as it probably wouldn't last too long, but that's your call. (You do you!!!....just stay healthy.)