That’s a tricky fit you got there. You could trim the stock tube back farther, allowing you to establish the new hoop line earlier. If that won’t work because your new hoop is a fixed length, then do a 2 piece join. Bend a small section of tubing at the needed radius to transition from the stock, to new hoop alignment. Weld the section in, then weld the hoop to the new transition section.
Or, a more complicated but less noticeable method is to cut a half lap from the stock and the new hoop, both with tapers so the new joint angle within the welded section. A bit hard to describe in words, but think about the change in angle, the height of the transition, then divide. You’ll end up with a small length of the transition being larger in diameter than 1” to accommodate the transition, but you’ll only have a single joint.
Slugs aren’t needed with this method. In fact, slugs aren’t technically needed in any of these, though they can be helpful. The hoop is welded to the frame, and the truss leg is welded, so there’s little to no likelihood that the hoop would pull apart if your welds are decent.
