Without getting really involved, I can't say if your material choice will certainly hold you but it sounds very reasonable (if not a little too strong). The sleeve material should be OK but you need to look at if you are getting "pipe" or "tubing". There is a difference in that in pipe the internal diameter is held very consistantly whereas "tubing" is usually the outer diameter that's held consistently. I suggest checking the details of the tubing you are buying...or test fit a piece...to make sure the sleeve will work.