The sump gaskets can be a pig, but your title and paragraph don't seem to match up. The oil pressure outlet obviously isn't anything to do with the sump - I've also never seen one leak on a CVH, so either the threads are shagged (on sender or block) or its just not tight enough, which can happen as it sometimes does feel like you're gonna crack the block.

If your sump gasket is actually leaking too, then are you using the multi-piece rubber/cork setup, or the one piece all rubber gasket? Original sumps I've managed to get both to work as long as the sump hasn't been overtightened and bent previously. I've never managed to get the multi-piece to work on aftermarket sumps, so tend to just grab a one piece. Trick is to glue the end half moons to the sump (just a drop) and that will keep it all in place when you line it back up and torque it. These sumps don't tolerate overtightening very well and then you'll inevitably get leaks as the bolt surfaces are all crooked rather than flat.
Oh and please don't just slap tonnes of gasket sealer on it - the gasket will just slide out of place and you'll end up finding most of it in your pick up pipe next time you drop the sump!