You're correct for the battery that come with the BSR. The battery that your align voltage regulator requires is a Lipo. 7.4V 2 Cell battery. I don't think 11.1 volts would be good for either the voltage regulator or your servos and am positive it will burn them up.(at least, positive I wouldn't try it). Also, check the 401 gyro. I'm pretty sure it requires 4.8 volts not 6V now that I'm thinking about it.
So the deal here is the Align voltage regulator with your bird enables to use a 7.4V lipo and regulates the voltage to 6 volts. Which is good for all of your servos including your specific rudder servo. in my applications that I use the align regulator I use even another regulator that regulates 6 volt to 4.8 volt that powers my gyro and rudder servo as my rudder servo is a futaba s9254 and requires 4.8 volts. Certainly time to use the brakes here and figure this piece out.
When I looked up the stats. on your rudder servo, it works on 4.8 volts as well as 6v.. I've studied your picture and cant tell if you've got another regulator in line to your gyro/rudder servo?
all of this has really got me wondering why someone would use a rudder servo that is designed to work on 6v for maximum performance and a gyro that requires 4.8v?



6v-4.8v step down