Not wanting to be a smarta$$ knowittall, but having fooled around for 40 years or so with aluminum, the correct thickness is .063.
Otherwise, a lot of good information here. As always from Rex.
For wrap around bodies, 5052 and shapes, 3003. Flat panels, strength might dictate 7075 T-6 if it's structure otherwise 5052. (.032, .040).
Nobody I know likes to gas weld 5052, the joint is ugly gray. 3003 with parent metal or 1100 rod is proper. Get flux from folks like Tin Man Tech these days.
I've been too timid to again try welding with Hydrogen, it's super clean but I wasn't ever able to set the flame right. Oxy acetylene, I can see what I'm doing. If anyone out there has mastered hydrogen send me a PM if you're in the mood to have your brain picked.
Have not bought much 3003 (H 14) lately but having to wait from May to August for a sheet of.063 from Aircraft Spruce of all places I'm wondering if the pending tariffs have affected the market???
Hume might have chosen .071 (hard to find in 3003) anticipating the dynamic pressures found at 500 plus.
IB