poly-tunnel hoop hut HELP

I know its Jan. & snowing BUT i wanna get started planing/building Early. Looking for resorces & info to get supplies LOCALY preferably. Tubing, bender, fittings, hardwear, ect..ect.. im in the spokane area. Today is Jan 21st 2016.
Heres what iv found out.
14g = about 3/32nd comes in 20' long @ 1 1/4 diam. Is 20.00 per stick. Im after 5' high side walls, so 22 side posts @ 5' tall on 4' center will give me 40' long hoop hut with side walls 5' tall. The top'bow' i dont know how to figer so i get enough pipe to make them. With 11 side posts per side ill need to make 11 hoop ( top,bow) pieces. How long do they need to be . My side walls will be 14' apart. Would like center of hoop high point be 8'-to-10

Good luck with your project. I once considered what you're planning but instead went with a prebuilt shelterlogic 10x20. It costs $382 but they can be found cheaper. you could do 2 for a 40' long greenhouse:

http://www.homedepot.com/p/ShelterLogic-GrowIt-20-ft-x-10-ft-x-8-ft-Greenhouse-In-A-Box-70658/204437675?gclid=CjwKEAiAoIK1BRCRiMqphvnlwlwSJAAOebPMkjDHcZk1NEYyxy1wcMW6OLvOI0TfFqBxNY29HoTYkhoCA0Tw_wcB&gclsrc=aw.ds

The walls are 10' apart, but straighter than hoops so have more useable space. My cover lasted 2 Montana grow seasons, the frame's in its 6th year, used by friends who just tape plastic to the walls, although he framed in a wooden door on one end.

That said I'm not trying to discourage you, and there's real benefits to hoops too. But for me this one penciled out. Good luck.