Surefire legos Newbie question

I am waiting on delivery of a L4. I also would like a single cell Surefire LED (brighter than El1 ... I already own an El2). I'm pretty sure from reading here that I could just buy an E1E and put the L4 head onto it. What are some of my other options if I wanted to try and make one myself? Recommendations for bodies, tail caps, etc... Sources for these items? Is it as easy as just purchasing these items (assuming they're compatible) and putting it together? Or should I just buy the ElE?

Also would I be able to put the head from the El2 onto this set up? (single cell)
Thanks

Hi! Im also a newbie regarding SF lego! I bought a L4 and a E1E, I can change the tailcaps, bodys and the bezels on the two lights. But when putting the L4 head on the E1E body I use a 3.7V RCR123 batt otherwise the beam is very weak. And when I put the E1E head on the L4 body you must use another bulb! Otherwise you will blow it! Bought a LF bulb that fits and needs 2X 3.7V RCR123 batts, 159 bulb lumen. But be aware! DO NOT USE theese batterys when using the L4 (KL4) head! It will breake it!

Thanks for the help! If I were to buy an E1e I wouldn't have any intention of using the head from the E1e except on itself. I don't need a single cell incan. I have a 6P and a 9P that cover my incan needs.

I am just looking to create a single cell option for my existing L4. I know I could put the head from my El2 onto the E1e but I have no need for that. I had read that sometimes the L4 head does not work properly on the E1e frame. That's why Im also curious about other options. (Aleph, etc...)

Thanks again