I just got the M60WF and YES it does fit the new style Pila GL3. I'm running 2 x 18500. Sometimes the electrical contact is not reliable but its just a matter of taking batteries out, shaking a little to reposition the dropin and reinserting batteries. Once it's all screwed down and working then the electrical contact is 100% reliable.
As for heatsinking, it's hard to say if the thermal contact is adequate, it certainly doesn't appear to be very good, but the head does get warm with use.