need help building a IR weapon light.

I have a surefire M961, I would like to keep the tail cap (for remote switch capabilities) and the body ( for the rail mount) but the Incan head and battery extender are a bit dated. I am not super familiar with Lego'ing the M series lights. what are the options for IR preferably 940nm+ that will work with my body? I know that Mhalkof makes an adapter head but its only their dropins I believe and they don't make an IR module. I am not sure if their conversion will allow any P60 dropin to work.

Thanks for any help.