transmission pan sealing

I have a 727 gasket sealing issue. Have tried every gasket imaginable including the plastic double bead sealing type with no real luck. (Rubber, cork, steel core with rubber, silicone) all leak. I have an aluminum pan that I had machined totally flat, a steel aftermarket pan, and even a steel pan from a newer model tranni. They all leak! All gasket surfaces totally clean before sealing. Major area of leakage seems to be near the dip stick part of the flange. You can even see part of the sealing bead on the plastic gasket in this area. I contacted Permatex, and they recommended The Right Stuff Grey (one minute gasket maker) Wanted to check here before trying my final resort with a more permanent gasket that will make things difficult to remove if it does leak. Have drained fluid probably 10 times. Have posted this problem before and tried every ones recommendations. Really wondering what people think of Permatex's recommendation or if you have any other solution other than epoxying the pan to the tranni. That would do it!!!