If I want to bring the flight down on my M3 440 cc driver, what is the difference between lowering the loft in the hozzle setting versus moving both weights all the way forward? Does one adjustment increase spin more than the other? Would lowering the loft by 2° and moving the weights back be more forgiving than moving the weights forward? What should I try first?
All else being equal, different lofts will always have a greater impact on spin numbers because you're changing impact conditions (in this case lowering/raising spin loft). Moving the weights will dial in spin and flight by moving the CG of the head slightly. The caveat here is that by adjusting the loft sleeve you're also changing the face angle slightly. For some this is no big deal and they deliver the club the same, but for others this changes where their ball starts.
In the scenario you propose, moving the weights back will increase the MOI of the head and add forgiveness, but it's possible that lowering the loft by 2° (and thus reducing launch/spin) would offset that. Personally, I always start by changing the weights and seeing if that gives me the launch/spin I want. If not, then I move the weights back to neutral and start adjusting the loft sleeve. Once I'm happy with launch, then I dial in spin with the weights.