[Grant-53]

[IMG][http://s1372.photobucket.com/user/shooky56/media/Rib%20problem%205_zpshwa0irj8.png.html][/IMG]
May need some help showing the link

This is the shape of a rib generated for a body for a recumbent.
Note that the top is wide at the shoulders and tapers toward the feet to minimize frontal area.

If you want to make hoops then make some wooden templates, get a good dead blow hammer or rubber mallet, and have at it. It will take a little practice to get used to the spring back of each material. Sheet metal workers use development drawings for ductwork which is similar to making a paper model or aircraft skin.