I made my first tangible progress on the project today (besides staring at eCalc and spreadsheets for hours). I got an appropriate conduit bender and experimented with making the 53- and 73-degree bends that I need for my frame. After the first attempt, I was able to make consistent bends to +/- 1 degree of my target, and the tubing is coming out pretty nice. Maybe not as nice as using a real tube bender with the appropriate dies, but it is not kinking and is only slightly flattened, probably about the same amount as with a tube bender on a stand.