The
TL3 would work well as a handheld adjunct to your weapon mounted light.
The TL3's non-standard body diameter only has two mounting options I'm aware of, and both are somewhat compromised solutions. The SL Thunder Ranch Urban Rifle Illum. Kit comes with
the bulky SL mount and a "shock-proof" TL-3. And bocrap sells
a fixed clamp which is much more compact but doesn't allow QD of the light. A rail to clamp the mount to is also required, whether it be on the barrel, front sight base, bayonette lug, handguard, or free float tube.
On an AR-15
rifle, a 9 or 10 oclock mounted light can be controlled with the left hand thumb (assuming a right handed operator), dispensing with the need for external wiring. A Surefire M78 or M79 ring/clamp holds a light securely, is easily removed from the weapon during daylight, and allows the light to be dismounted for handheld use. A WG9D light body with a Z32 bezel, P91, and E series tailcap switch will provide 200 lumens/20 minutes. Contact Grant at G&R Tactical.
On an AR-15
carbine there is not enough room for the light and your hand on the left side. Many, many users mount the light with an offset mount on the lower right side, about 4 or 5 oclock, and again access the rear tailcap with their left hand thumb while wrapping the left hand around a VFG.
There are many variations possible, but the above two methods are simple, ergonomic, and highly reliable. HTH.
Paladin
ETA: I think 9 volt lights are better for a physical "form factor" reason, their length puts the tailcap switch where it needs to be, while allowing the bezel to be far enough forward to avoid lighting up the side of the front sight base.