I was always confident that I did the right thing and blamed leaks on a poor factory design. I've sealed up transmission pans using that Mopar rigid plastic gasket, that is what led me to believe that trying something more modern for the oil pan might help.
I usually do attach the gaskets to each side of the windage tray and let them set up. The idea of bolting it all to a piece of plywood is interesting. In a similar way, I could attach it all to a spare 440 I have on an engine stand.
Studs? I like that idea....except for the area at the very front above the K member. Access is tight there as you all know.
In 2004 when I first built this engine, I had it on a stand and used pan head, allen fasteners. I thought they looked cool but later when I wanted to pull the timing cover to do a cam swap, I found that the 4 bolts from the pan to the timing cover were a real pisser to get to. The hex socket for the allen was like a deep well socket. I had to cut down an allen wrench and back those out 1/8 of a turn at a time. Its funny how you can screw yourself up when you don't think ahead.