I think that FOC or front of center is the biggest thing in figuring what weight head you oughtta use. Thats a measurement of how far front of the center of a finished arrow it ballances at.I shoot 100 grain & have been told its too light because I shoot 2219's & they are a heavy arrow. They fly great tho & I didn't know I was breaking a rule till they told me at the shop. They had set me up with 100's using 2413's & theyre alot lighter & I switched without consulting them.
They tell me alot of guys shoot light carbons & can use lighter heads & still have a decent FOC.
I guess in your spot I'd just shoot both & see what happens. I never shot a lighter head but have shot 125's & they fly fine too, just not to the same spot but I'd hunt with them. You may be fine with either or one might fly better. Try them with broadheads tho too.