I haven’t welded but from what I’ve seen of framebuilders discussing it, doing one side first will pull the tube to the side and out of straight (obviously) but then moving on to the other side won’t pull with the same degree because the original weld has added rigidity so you still end up with the tube pulled slightly toward the original weld
yeah i think the reason is that the tubes can roll quite easily inside the mitres and unstraighten the frame, but if your mitres are tight, it shouldnt be able to change the geo much as it would have to compress the tubes or something.
I haven’t welded but from what I’ve seen of framebuilders discussing it, doing one side first will pull the tube to the side and out of straight (obviously) but then moving on to the other side won’t pull with the same degree because the original weld has added rigidity so you still end up with the tube pulled slightly toward the original weld