I have the Thunder Ranch rig on my carbine and have been happy with it. The TL-3 does throw out a LOT of light (211 lumens supposedly) and the mount, while a bit bulky, is bull-strong. Mine has survived several hard drops so far and hasn't loosened at all. I also like being able to remove the light easily to use for other things. It only takes about 3 seconds to remove the light and not much longer to put it back on.
ETA- You also mentioned mounting it to a standard set of carbine hand guards. I did it myself and it wasn't too much of a hassle, but you need to have some skill as a tool-user and pay close attention to what you're doing. You don't have to drill any holes as long as you mount it in the 6-o'clock position, but I wanted mine mounted in the 10-o'clock range so that I could manipulate the light with my left hand and so it wouldn't interfere with my sling.
As such, I had to remove the handguards, mark the desired mounting position, mark the position of the holes, and drill holes through the upper handguard AND heat-shield. The holes in the heat-shield were to be 3/8" in diameter, and a 3/8" drill bit really tries to bite and tear the aluminum. Take it SLOW, read and re-read the instructions very carefully so you can get it right the first time. If you are not good with tools, I would strongly advise you to find someone who is to do it for you.