bigjohn,
If you want to set your main speakers to large, all you have to do is turn down the crossover knob on your subwoofer until you find a point where the bass matches well with your mains.
At the present time, i have my M60s set to large and i run the crossover point around 50-55Hz. Some receivers will allow for a lower crossover point (less than 80Hz)such that you could still use the receiver to keep your mains set as small with a lower crossover point, but my receiver does not.
I much prefer more of the mid bass to be handled by the M60s. It is not as muddy and predominant. The subwoofer is left to handle the truly low end notes. Be careful you do not turn up your receiver too high though as the extra power required for the M60s to hit lower bass sucks back the watts.
