With the tank modification, you're pushing fuel away from the petcock... just a "caveat" for you.
On your swing arm welds, you need more heat. Cold toes are weak welds. The edges of your welds want to be fully fused into the parent metal. Rounded up, or "humpy" welds are indication of lack of penetration/too low amperage. You can run your TIG torch back over them now, no filler, and wash them in hotter for stronger results.