Don't know if this is going to help you or not, but it would take your rig out of service for a day or so. I've used the following method to stop leaky pans/covers/grandmothers/whatever before.

I'm assuming you're starting with surgically clean surfaces on the pan and trans.

After cleaning all the old gasket material off both surfaces, I start with green ScotchBrite pads to get everything extra clean. Then take some 200 grit sandpaper on the transmission mating surface making sure you sand in one direction parallel to the mating surface. The idea is to make tiny grooves in the surface for gasket maker to work its way into. A microscopic obstacle course of sorts that the fluid needs to go through to get out. Kind of like /\/\/\/\/\/\ around the entire surface. Hard to explain online.

After cleaning all that up, apply a thin layer of RTV (I prefer the grey) to both surfaces and let it tack up a bit. Not dry, just tacky. Then install the pan but only finger tight on the bolts. Let it set up overnight, then torque the pan bolts to spec. It's letting the gasket maker set up in an expanded state, and allows for some *squish* once the bolts are torqued down. If that doesn't work, then something else is going on.