Yes, it only takes once!! And your yurt has already had some misfortune, Dan. I suspect that the reasons the Mongolians started keeping the center posts up even after set up was a situation like that... someone got hurt by a falling ring or something. I was talking about that with Becky Kemery at some point. She has another yurt blog and wrote the book, Yurts: Living in the Round.
H-66 is definitely not a Home Depot/Lowe's thing.

Online is the way to go. Sorry to hear about the leaks... nothing dampens my yurt spirits quicker than a leaky yurt

But at least you're in a dry climate!
The rafter locking screws are great.
do a sunken bolt/stainless steel 'cable catcher' at the end of their rafters. Love them. And then they also do the CORR bracket system, which is something I think every yurt should have, period. Then, no matter how that yurt may rock and roll, your rafters aren't coming out from the top or the bottom. The CORR bracket is in place of the peg at the end of the rafter that goes into the roof ring. It's a double sided bracket that slips over the end of each rafter, and a bolt goes through the rafter and bracket.