I'm using a regular green BelRay grease on and in the driveshaft. I have the same one you do, Jack, the Emrald Isle one?
Those are pretty good ideas, Cpt. I'm not sure why it pressurizes, other than an enclosed space that changes shape a little bit and heat ups and down, etc. When it does though, I think it pukes the grease out of the bearings, backwards, I think. I like the idea of a different vent than the SA bearings, but maybe something like the airbox valve. That valve is uncomforatable bigger than 3/32 but maybe there's something similar out there.
It aint a fit night out for man nor beast.