I email the guy who made it and ask him to log in and answer some questions, not sure if he will or not.
On another note, Denny's Driveshafts offers a twist and tear lifetime guaranty on there steel shafts. They cost around $350-$450, a bit more then I wanted to spend, but maybe a good investment for Brian's 'Bird. This is what they said
“We stand behind all of our Heavy Duty driveshafts....so remember "IF YOU CAN POSSIBLY TWIST OUR TUBING OR BREAK OUR WELDS...WE'LL REPLACE IT FREE!!! That’s the kind of quality and confidence you won’t find elsewhere” Here’s there web address
http://www.dennysdriveshaft.com/index.html