Yeah, gotta love this aftermarket stuff.
Make sure it's not leaking from somewhere else first, like a pinhole in a weld bead, or something like that.
I use the rubber nitrile gaskets from Felpro, but the cork works just as well.
I glue the first gasket on with tacky gasket adhesive, making sure to cut around the rear main cap bolts/nuts with a hobby knife, also making sure to cut around the rear main cap drain hole. If that drain is blocked, you can get a rear main seal leak...
You can lay down a layer of lithium grease or RTV on the gasket, then put the windage tray on. On the FE Cobra pan, the
oil pump pickup bolts to the windage tray, so you have to put the tray on first, then bolt the pickup to the pump and attach it to the windage tray stud.
You can use the gasket adhesive or RTV on the tray, then lay down the gasket, again, looking to make sure that everything clears on the rear of the block. I use another layer of grease or RTV again, then bolt the pan up.
It seems that heat cycles really get to these things, and if you use fasteners without lock washers, it can contribute to the issue as well.
A lot of my customers seem to like the appearance of the Aviaid pan over the others, but the truth of the matter is that I've had more leakers than non-leakers.