Oscar.
I use a TDI mount for all my lights. I've taken to mounting the lights on the 9:00 rail and activating the buttons with my thumb - note I am right handed if you are a southpaw put the light on the 3:00 rail. The grip I use on my VFG is to cup the fingers around the VFG and have my thumb resting on the 9:00 rail (sticking straight up in the air). Takes a little getting used to but makes for a more stabil hold (thanks to Pat R. and Tim L. over at 10-8 for recommending this trick).
When I was using a full fist grip on the VFG I still used the TDI mount. Only I also added a YHM 3 slot angled dovetail mount on the 3:00 rail. The YHM angled dovetail would be loctited in place, but the TDI allowed me to remove the light quickly and easily as needed. The combination of the YHM & TDI mounts put the light in a perfect position for me to use my thumb when using a 'Choking-the-Chicken' hold on the VFG.
Hope this helps.
EditI got both these products from Brightflashlights. My TDI mount works well with the plastic AND aluminum Surefires, also it's worked perfectly with the Elektrolumnes XM-3 and my Inova T-3.