Hi Joe,
If I were doing this I would do the following. I would run both regulators into the PowerExpander. I guess you have them matched well enough that you do not get uneven battery draw which is lucky. Usually you get one battery going down faster than the other when two regulators' outputs are tied together. Next I would use an Equalizer II in each wing. I would plug one of the 8611As into the the PowerExpander directly and I would use the Equalizer II to match the other two servos to the first. You would use your transmitter settings to set the center and throw on the one plugged direcly in. I would use the Equalizer II on each elevator half unless you have them matched mechanically well enough you are happy. I would split the ailerons for sure and you can either split or not split the elevator depending on how you configure your mixes. On the rudder I would use two Equalizer IIs for the four servos. You get the best power this way using any matching device. You might also consider an Ignition Cutoff. Hope this helps. Let me know if I left anything out.