what did you do, park it in 4 low and dry drag it?!?! Delete that vid before he sees it... definitely a bad idea for MANY reasons.
Anyway, I have had a couple of pro welders tell me if your not going to do the prep work, don't bother powering up the welder. You might have voids under the weld pool and it is sitting on the surface. It's a great project, but your better off pulling them off before somebody gets hurt. The nice thing about working with metal is you can grind off the welds and re-use alot of what you have there. I would suggest taking those extensions you added on, along with the pieces that were too short, and just spend some time practicing and getting your grinding and welding techniques better and fine tuning your machine for that thickness metal.
2005 Jeep Wrangler Rubicon Unlimited Sahara Edition #603 of 1000 - aka Betsy - DD
1978 Ford F250 Ranger XLT Camper Special - aka Big Pig - off the road but not forgotten