Back EMF: drive 2x10

I'm building an active 4-way system where the midbass (80-600 Hz) will be driven by two 10" drivers per side. How should I drive them?

a) Drive both 10" with one 700W amp with both drivers connected in parallel to the amp.

b) Each 10" driven directly by one 350W amp and both amps driven in parallel from the crossover.

As I was modelling the effects of baffle step diffraction, boundary reinforcement, etc on each driver it became apparent each will experience a different response and hence will feed different back EMF into the amp.

Conceptually this seems to be right. My question is how much does this all matter? Maybe it's a fringe benefit and hardly audible considering the range this will play at and the size of the larger amp being considered?
Should I go with the bigger amp and keep it simpler, cheaper, and call it a day?