Tinker,
I have been following this thread but thank God have nothing useful to add. I am on my 4th build, with a 5th partial waiting in the wings. Through a combination of strong host guns, close tolerances, and over-build, I have never had a problem. one has to always be aware that a catastrophic failure could result in crippling injuries or even death. It's always enlightening to share efforts and results with people who have "been there and done that". It's also scary as hell to read some of the suggestions by others who have not.