NHRA Welding rules??

Well I am stitch welding the floor back in and to the frame connector, not too worried there. I put a 3 x 3 plate on the torsion bar cross member first and started welding it there and forgot to turn on the gas. So what should I do there now? I am not real confident mostly due to lack of exp with welding. And also where I cut the rear frame rail open I opened it up to far and the 2 x 3 tubing does not fit tight, How do I go about closing the gaps maybe 1/8 to 1/4 inch wide? Also cleaned the holes further back in the original frame and welded connector there also