I bent all of the tubing and TIG welded the canopy frame on my F1 from scratch (tipover). At the front when I had to bend the 3/4" square tubing to match the top of the panel I made a wooden template out of MDF, and sanded the outer corners down to account for springback. That got screwed to a larger piece of MDF which was clamped down to my work table, and I bent the square tubing around the template by leaving the square tubing extra long and just manhandling it. I also used some scrap blocks spaced 3/4" from the template to keep the center from bending as the side corners were bent. A lot of waste that way but the square tube matched the panel curvature almost perfectly.
