I have 2 1650mah 6V packs in parallel in my Edge 540. They are just plugged into the Rx and the power 5 8411's (and a mini servo) with no problem. The servos don't jitter at all, even when both packs are fully charged. I have only heard of people using regulators when the servos can't handle all of the voltage. I am sure there people with more experience than me though.

Bob