The two elevators, either of which is redundant in the event of a failure, could make the difference between having an airplane or having a smoking hole. I hope none of us make use of the redundant surface and servo, provides but since it's there, why not look upon it as insurance?
The bobcat will NOT fly on one elevator half. Trust me I know. If you want a redundant system, just use the two servos but do not separate the elevator into two halves. The bobcat I am building now will be using JR 8411's or Hitec 5945's. In the event of a failure one servo will drive the entire elevator without a problem.
As far as the original question. JR Servos will work with futaba gear. I "used" all JR servos in my last bobcat with a JR G450 gyro with a R149dp receiver and a 309DPS synthesized receiver without a problem. Tranmitter was a 9Z
Patrick.