I have done a lot of research on the web forums and other builder's blogs. I ended up trying several different techniques.
The process is very subjective and involves bending then checking then bending more, etc.
This is a popular technique with wood brackets to hold the bending tube. The skin is taped to the tube with duct tape. 
After the bends are made there is a good bit of effort involved to get the skins lined up for riveting. 
Posted with Blogsy