You talking low light with a rifle or pistol or both?

With a rifle I prefer a pressure pad. I generally shoot my rifle with my support thumb on top of my rail. I have my pressure pad mounted a couple inches behind my front sight so my thumb rests in the gap and only needs to move back a smidge without grossly altering my grip to activate the light. Not a fan of tail cap activated lights as I have to alter my grip more than I want.