I have a surefire scoutlight with a tailcap button. It sits where my support hand naturally rests and also serves as a handstop. I had a tape switch for it, but switched to the endcap button and I like this setup better. Less stuff on the rifle.
I run a Surefire X300A at the 12 o’clock position just forward of my front sight. Momentary or constant on are both easily utilized with my thumb. Works for me.