If I wanted to try a 26" DL on my Reflex Grizzly (60-70, 27-30) could it be done merely by swiching modules as with higher end bows adverise? It has the Hoyt cam & 1/2 cams. Also if it can be done, how will it affect draw weight, strings etc?

I might be possible I was talking to a fellow who contacted hoyt/reflex to see if he could put hoyt limbs on his reflex riser and to make a long story short he has a set of limbs on the way to his door. As for draw length mods I would contact hoyt/reflex personally you will get the answer you are looking for.

You will need new cams to get down to 26". The modules only change the draw length within the specific range for the cam that is on the bow. In order to get outside that window you will need new cams for sure, possibly new limbs depending on the deflection of the current limbs. I am not 100% sure on the limbs, but you will definitely need new cams.