Well, this was a bust. Or at least not an improvement.
Got a custom gasket, installed the pan and gasket with a very thin bead of RTV on both sides of the gasket to glue everything together. STILL leaked around the center rear bolt hole.
I've already removed the pan again. I think my next step will be to sell it and either go back to stock or pick up another cast aluminum pan. I'm pretty bummed about this but I don't see a real alternative.