Well the results are in: using the wax paper instead of vaseline was a major success! The only issue that I ran into was the temperatures not being warm enough to setup the silicone so it took even longer than I had planned in some of the thicker spots. She is air tight, not even a whisp of air coming out anywhere except the exhaust.
I built a large coal basket for the firebox to test how long an 18lb bag of lump will last with a stoker set to maintain a cooking temp of 275. Thanks Trent (TTNuge) for letting me borrow the stoker, if it goes well I will be buying some sort of temp controller. It won't be the super hi-tech stoker though, way to much technology for my simple mind.
I have the cooker fired up right now for brisket, salmon, chicken thighs and a couple of fatties! I'll try to capture some pics of the silicone gasket after the cook today!
Here is the cooker in action! It seems that I always plan the best days to cook on: 25 degrees and a pretty steady, cold wind out of the north!