I used the following digital servos on jets: S3050, S9350 and S9152. all of them worked very well on elevons, elevators, aleirons, flaps, speed brakes, etc. at non-regulated 6 volts.
In 25 years in r/c activities I never had a problem with a new futaba servo. can“t say the same
about other brands.. (and yes, I tried some of them)
Best regards, Enrique