I'm very interested in this too.
Just got 6 7955TG servos and plan to use with 6014FS (which goes as low as 2.7V p-p square wave pulse on the servo signal line)
The general servo info sheet that came with the servo says
PULSE DATA
All Hitec servos require 3-5V peak to peak square wave pulse.

Is this literature (version 2) out of date or incorrect?
thx
Gator