I have an MGW shifter and the gasket and I still have the noise. There is no gasket for where the handle attaches to the shifter (which probably would help)
what if a small amount of the silicone maker that comes with the shifter was used where the handle connects to the shifter, this might help as it is another gasket formed on a metal on metal connection like that of the shifter base to tranny. you would have to make damn sure of your handle position as well as tightening the handle down.