Run one stereo amp per speaker.. In otherwords dedicate one amp to run your left channel using the left or right channel to power the woofers and the other open channel to run the mids and highs.... This is verticle bi-amping, reason this could work out better than Horizontal bi-amping is that you can use a little longer interconnect and set the amp closer to each speaker with shorter speaker cables..
However, this is not the main reason for doing this, it is because especially if each AMP has a single power supply or transformer in it which most do unless specified as a Dual mono, than you are now Splitting the power supply with about 20 % to the mids and highs, and 80% left over to run your bass. Why? Because if you run one amps in the horizontal config for both Bass drivers in both speakers than you are now splitting the signal with less power available to the bass drive at 50% each.
Your mids and highs do not take much power at all, even if not the most efficient speaker, its normally the bass load that will cause the draw from an amps caps and transformer, so now in a verticle config you are not wasting one whole stereo amp seperating that power supply to just run both channels of mids and highs? Sorry if this is hard to understand but its as basic and graphic as I can explain on the internet.
Good luck, just think about it and it makes sense, do you want to dedicate one amp to taking on both Bass units? Or have a bigger reserve for bass current simply just talking a stereo amp per channel, by the way then you just need a basic jumper to connect the left and right channel RCA's right together on the same amp with the same signal, and you get less crosstalk as well cause you are now just running all one channel thru one amp instead of splitting it.
