please accept my apologize for the short brief response earlier. i needed to get to a meeting. i sensed your frustrations and wanted you to know that we are here to help and i was trying to get you an answer fast. here are some more details on this issue.
with the BD unit alone, you are only capable of 8 channels. for me, with my gassers, i needed 9 to utilize all functions. that is my pitch, throttle, rudder, elevator, aileron, head gain/horizon, tail gain, gov HS selection, and Gov on and off.
to get more than 8 channels, you must use an external RX with the wire loom, and use your Aux 3 and 4 channels as your extras. it is a little more complicated, and a little more of a mess, but it works very well. it is also much more reliable as the BD and Spectrum history of brownouts is very well documented. using the external rx will allow the power to sag down to 3.3V (IIRC) before a brownout, where the BD will only handle 5V with sats only before it browns out.
below is a wiring diagram for the external RX. i took this from another site, i did not make this, and cannot take credit for it. it is very nice though. notice that these external RX in the diagram only go to 7 channels though, so just imagine an aux 3 and aux 4 ports there for your use with your gov and your switch glow.
i cannot help with the low voltage servos though. other than running step downs to each servo, i dont know what to tell you. i run all HV stuff so never had to do this. you may want to use a 2 cell lipo into a CC BEC Pro to get the power down to your proper voltage for all of the servos without having to run step downs, or a regulator. with the BD and spectrum, the higher the voltage the better, take a look over on HF at all of the threads on brownouts. i run 8.5V on everything that still has a demon on it in my fleet.
someone that has run a regulator can help you figure that out, i am sorry, but i have never run one before.
