Thanks, but I think I found something that will work. Its between 5/8 and 3/4, so it'll work. The only place I found 5/8 aluminum tubing so far is parkrose hardware, but it was way to thin walled.
Yeah, I'll be at the roseburg event (
http://www.eescc.org/ for those who don't know), but I probably won't have my new spring in for any event this season.
Aaron