definatly try the 3/64 first, imo it is the perfect size. the rsst comes with a very tiny air hole so imo you need to open her up, this will help a lot. be easy with the drill bit, it doesn't take much to go through the very thin top cap of the rsst. also with these low resistant coils, with a good wick and coil you should be able to hit the fire button with a full tank of juice and the mod vertical (without the top cap on) and the coils shouldn't light up. if your coils are glowing at this point there is to much heat being produced causing problems.