As a helicopter pilot with some 3000 hours, I am really impressed how the pilots are able to hold that steady of position with very little Fore/Aft, lateral or vertical movement.

No doubt, they have glass cockpit with very sophisticated GPS, and most likely vertical hold capabilities. With the Hoist Operator providing all the info for the small corrections, the pilot probably makes these adjustments with a Chinese hat on top of the cyclic, or some other way to provide the instruction to the GPS. "Right 5, or back 10"

Also note that the hoist operator always provides the pilots with a "Clock Position" of the location of the swimmer when they are in the water. I would assume this info, is provided to the pilots in case of an engine failure........when you settle in to a hovering auto rotation, try to drift away from the swimmer.

Certainly not to take away any of their very professional piloting skills, but I would think that once they are over the pick up zone, they turn on a very good autopilot and make the small adjustments when required.

Joe