doing some research myself. You used stainless tube. It weighs roughly 1lb/linear foot. I also see they sell aluminum tube. The weight is 1/3 for roughly same wall thickness and diameter. 2/3 for double the wall thickness.
http://www.onlinemetals.com/merchant...=71&top_cat=60
did you do any research on whether the aluminum tube in these thickness was up to the task. There is a substantial weight savings for the thin was. still some for the thicker stuff. Just curious.
Mike