I'm in the process of mixing and matching some parts to build up a new weaponlight for one of my AR's.

At this point I've got a Malkoff M61 that I intend to use with a surefire 6P aluminum bezel.
(I also have an old shock isolating bezel but it's my understanding that these are actually detrimental to heat management vs the stock head when using an LED).

So along the question of heat management, I have a few bodies to choose from.

Would I be better off using the aluminum 6P body or a polymer G2 body?

The G-2 body is lighter and actually fits more snugly in the mount I plan on using which is an old VTAC offset.
I'm leaning toward the G2 but if I'm going to sacrifice performance and longevity on the setup due to poor heat sinking I think I may use the 6P.

Tailcap will be a momentary to match whichever body I use until I pick up a clicky cap.

Any thoughts are appreciated.

You absolutely should use a 6P body.  The G2 body doesn't conduct heat at all, which is bad for the Malkoff drop in.

Kind of what I thought, I was hoping I was wrong.