As Diablo discovered, buffers and amplifiers are just a needless expense that very well may make the problem worse. Until you start flying airplanes with 100 ft wings forget them. You don't need an amplifier on a 10 ft wire. The input resistance of the servo is in the order of 1K. The resistance of the wire is less than 1 ohm. This means the line loss is 1/1000. About 0.01 %.
RF reflections? Buffers and amplifiers won't help that. Their purpose is to restore line loss.