Well, it looks like about a 5 foot radius, and about 10 foot lengths of tube. Test it on a length of tubing first. Smooth your saw cut with a rasp.
Copper is real soft.
Screw some curved plywood strips to the cut edge. The part of the plywood you discarded can be cut into two strips. Now you have a square groove for the tube to rest in. Mark off the middle section of the tubing that needs to be bent. Secure the jig.