3/8 Tubing Straightner / Roller

I make a lot of projects that use 3/8" aluminum tubing and one of the things I hate is that it is sold on 50ft. rolls. Which doesn't help much if you need straight pieces. So I made this roller to be part of a 3D printed tubing straightner. However, the base undured too much strees and flexed too much to make a usable tool. So I wound up using a piece of 3/4" plywood. This works better than anything that I have tried up to this point. It still leaves an ever so slight arc in a 3ft piece of