All MetalShaping - Howdy from Coeur d'Alene, ID

I'm new to the site but have been building cars since I was a kid, which is now a long time ago. This last one, a Prius powered '64 VW bus, is the first I've done serious metal work on. Learning to do major panel replacement as I go, as our old bus was gone from the floor down outside the frame rails.
I'd love some info on spot welding options. What about weld-thru primer?
Old projects:
27 Chevy 4 door with Y block V8
55 Chevy straight axle gasser
32 5-window Ford Coupe w/ smallblock Chevy
61 Morris Minor sedan
59 Morris Minor pickup
67 Morris Minor ragtop w/ 1275
56 Volvo wagon w/ Eclipse 2.0L turbo AWD running gear
87 Vanagon w/ 3.0L Maxima V6
And now this bus...