[ERA Chas]

I'm about to R&R the Canton pan and windage tray on my Sideoiler for the umpteenth time to stop leaking/seeping at rear gasket area. The block plugs at the rear bulkhead and rear main are not leaking. I've used everything by FelPro, Mr Gasket, Detroit Gasket and am about to try Milodon 40450's. RightStuff, Wrongstuff, HiTack, Lowtack and everything in between has been used without success. I sandwich the tray with a gasket on each side, studs and nuts attach the pan unit. Made steel load-spreading bars for both sides and front/rear. I've also tried no sealant, dry installation. No help. Am considering axle grease on the mating surfaces which works perfectly on the valve covers.
I've done all the easy things like ensuring flat surfaces on the pan and tray, no squishy applications of silicone and I do not overtighten.
Please advise how you send dry motors out the door which don't come back. Name the brands of gaskets and sealants you use. All advice greatly appreciated.