Cut off for the LC is 2.7V IIRC. I'm thinking that output on the higher levels would be dropping off quickly before you get close to the cut off point though.
I think it's direct drive, so I wouldn't use an unprotected battery in it. You might ask at http://flashlight-forums.com/index.php as that's Mr. Bulk's forum
Do you know if it has the original LC board in it or the Chameleon board, I have heard a few have been modded for the Chammie LE? In regards to the unprotected batts they will work with either one as far as I know.