Really? I would have thought that it would be needed even with the gasket. I'm glad to see that yours has been holding. That makes me feel a little more confident that this may actually work out.
I can't imagine that it would hurt to still add the o-ring as a backup just incase. I may also try to make a couple of additional gaskets out of some industrial type material as kind of a back up if the fiber ones fail.
Do you recall any other problems with yours?
Thanks
71muffin