Nice drawings Pete! This should be a relatively easy project, if you have a tubing bender and welder.
Great pictures! good Info! I should have it from here... Thanx PD and Rick
I'll let you in on a little trick my broyher-in-law showed me...
cap one end of the tube fill with with play sand and then cap the other end of the tube, place the tube in a vice and heat the back side of your bend with a torch untill it turns a dull orange and make your bend slowly. The sand will keep the pipe/tube from collapsing. uncap the pipe/tube and dump out the sand.
I used this trick to make a 2" coil out of 3/8" copper tubing for a still head condenser.
GaryS