A few years ago I purchased a set of oversized banjos from Genos and never got around to installing them. I recently installed a campaign pump and decided to install the banjos. They threaded into the pump very hard and left metal chips when I pulled them back out so I used the original Banjos instead. I seem to recall that this was an issue with the plating on the banjo causing a tight fit and not a thread size problem.
In regards to the campaign pump, I've had it on for about fifteen hundred miles with no problems. In series with the 7 psi pusher pump I get 23 psi at idle and 17 wot.