Front "China wall" sealing issue on SBM

I have a 5.9L Magnum short block in my '70 Duster with Edelbrock open-chamber heads and RPM non-Air Gap intake. I have a recurring issue where oil is leaking out from the area on the passenger-side bank where the head, block and intake mate together. I assembled the engine using the 'big bead of RTV' method to seal that area like is commonly done with aftermarket intakes and heads. It started leaking not long after getting it running so I pulled the intake and carefully cleaned and liberally re-applied black RTV to the area; it didn't last long and started leaking again the same as before. The leak isn't that bad unless the engine is running at higher RPM (above 4000 or so) so I've just been turning a blind eye since then but I want to start taking it to some local track days and I know running on a road course it's going to be spending a lot of time in the higher revs; I don't want to get in trouble for leaking oil on the track and/or running low on oil. Plus it's just irritating as hell and makes a mess. Anyone have some tips on how to reseal it and make it actually STAY sealed this time around? I've moved on to using black Right Stuff sealer upon recommendations of others which I will use for this job. I also recently found a YouTube video by Dead Dodge Garage where he had the exact same issue on a 340 running these same heads and a Weiand (iirc) intake manifold, he hasn't reassemble the engine yet though so I'm not sure if he has a solution in mind.

He first starts talking about the sealing problem around 3:30-4:00-ish mark...