The ds760 and Quark gyros feed power the servo from the black rudder plug. The gyro itself gets powered from the red gain plug. If you want to use a voltage regulator or step-down for your servo you may fit it either before the rudder plug (between the receiver and the gyro) or at the servo plug (between the gyro and the servo). Either way works equally well and you can therefore choose the one that best fits the wire routing on your helicopter. The gyro will happily work from unregulated voltage up to 8.4V and thus it can be powered directly from a 2S LiPo battery.