Basic questions about a custom/modded light for use as a weaponlight?

I debated whether this should go in the "recommend me a light" forum, or here. Being that most of my question pertains to a custom configured light, I chose here. Hopefully ya'll can help me out! I'm looking for a single cell light to mount on the forend of a rifle for use as a weaponlight. I need the light to be mounted in an offset configuration, which rules out the surefire m300a, though I'm interested in the comparable VTAC mini L4. However, I'd still like to consider other options. Due to the difficulty I've had in finding other single cell tactical lights, I'm very curious about the possibility of a custom configuration/ 'lego' built light.... However, as I've never done the mix & match thing, and have only a minimal understanding how the electronics of a light work, I have some pretty basic questions.

concerning the single/multi cell capabilities of LED's

• Can an LED head/module from a multi cell light be run on a single cell? ie, could the KL4 head from my surefire L4 be run brightly on an e1e body?
• If not, would it be possible to have someone install a new LED into the KL4 so that it would run on a single cell? would this eliminate 2 cell useage?
• I'm considering a P60 LED dropin + C2 head(Z44) + adapter + e1e body. Would an LED dropin purchased for such a configuration also be able to be run in a 2 cell light, such as my surefire C2?

anybody who can shed a little light (pun intended) on what type of configuration would be best for me to go with would be greatly appreciated! any recommendations for people who could do the electronics work would also be nice. Its important that the electronics be able to hold up to recoil.

I guess this really boils down to a 'recommend me a modded light' type thread

shoot, 2x123a capabilities aside, I'm having trouble even finding a P60 dropin that will run correctly off of 1x123a... I thought I was beginning to understand the specs, but after talking with a few dropin makers, apparently not ... I had figured that a dropin rated 2.7 to 6 volts would run well off a single 123a, but it seems runtime would be extremely short.

It seems that plenty of 1x123a production lights have a great balance of output vs runtime, why I am I having such trouble finding a p60 dropin that behaves similarly? ~200 lumens for ~1hr, would be just fine, and have several production lights that perform this well if not better. Do I simply not know what I'm looking for, or does such a thing not exist in p60 dropins?