This was definitely the hardest joint to do took three attempts. Tried twice with thin tube cut to height but trying to work round the clamp and the thin tube meant I just kept blowing holes. Found some thicker tube. Did manage to put a hole in this one too but the results came out much better having a long length held in place by the 3rd while I tacked it in place so I didn’t have to negotiate the clamp as well. Cut it down to size ounce it was welded in place. The rather big and unwieldy torch didn’t particularly help in this case.