I'm in Costa Rica, so no Lowe's and the Ace that went out of business didn't have squat. At this point, if I go tubes I'll just roll them out of thin aluminum sheet. I want the aluminum so I can easily monitor for thermal charging, as well as dissipate the heat really well. It wasn't the sprung ends I was worried about losing connection, but more in the middle of strings and the contact from one battery to another. If it works with the acrobatics of RC, and you aren't having issues going fast with a suspensionless ride, then my worries are probably without merit. Now to figure out how to make the tubes an integral part of the strength of the frame to save weight in that structure, hmmm.
Thanks,
John