DB, for the distances you describe 16ga wire would be plenty, but the problem is that $100 for 100' of it is far more than necessary; $30 would be more reasonable if you need 100'. Consider returning that Monster.
As far as making the connections equal length, total nonsense. It would take a difference of miles in length for the signals travelling at nearly the speed of light to have an audible timing difference. If one was say 100' longer, then the higher loss would lower the volume on that speaker the slightest amount, but calibrating volumes corrects any imbalance.
It sounds as if you want to run speaker wire to the sub and then on to the M60s. Your 335 has good bass management, so there's no good reason apparent for wiring that way. Use a coaxial cable(not speaker wire) with an RCA plug on each end from the sub output on the 335 to the low level input on the sub. Wire the M60s directly from the 335 with the 16ga speaker wire. Set all speakers small with appropriate crossover points on the 335, probably 80Hz for the M60s and maybe 100Hz for the others.
