So you finally hit a subject I know something about!
My son and I had a mountain buggy business here in PA for two years building 4 banger VW powered 2332's that ran on CAM2 and Nitro methane. Test ran them at the coal waste hills at Treverton and Minersville PA.
Our buggies saw a lot more abuse on coal mine roads, rock fields etc than the normal sand buggy sees. What we found was the more you put weld on the tubing, the more it was at risk of breaking. We used a special tubing notch cutter (sort of a belt sander inside) to make nice tight coped joints, thus there was not much of a need to fill large gaps. We always used the weave method. We would take the buggies out, beat the Pi** out of em and see what broke. I would much rather have a somewhat ugly weld that held up, than something pretty that broke and ruined a day out (not counting towing time). Somewhere I have pictures and there is a YouTube video. Will look for them when I have some time.
Don't over think it. If you have two buggies sitting at a show, one is all nice and clean with pretty welds and spiffy paint job, and the other is covered with mud and coal dust and it looks like it took a beating...that's the one folks crowd around.
Edited to add: We used a Systematics "Fender Mender" MIG. Nothing fancy. It was old and used when we got it (10-15 years ago) and we still use it.
