Hi all, just acquired an Armstrong board and wondering how tight the vent screw should be? Obviously not very tight as it's a plastic thread and the o-ring is pretty soft. At the moment it's just to the point where the o-ring is squished enough that its outer edge is just visible when looking straight down at the screw. This was light finger-tightness when turning it with a 16mm socket (just the socket, no handle!) The internet has very little on this matter. Any official instructions or learnings from experience appreciated.

You are spot on

Oh yeah and conscientious manufacturers- only one I am aware of so far hmmm - put a smear of silicone on the threads as Baldy suggests.
but very very little - if too much it will seize up and later removal will snap the head off. Also be very very careful not to get it on the membrane of course. They don't vent much as it is