One thing that surprised me about that video was them tossing the winchman out at anout 100 ft.. I can appreciate the downwash being to strong to hover at 20ft or so but we had the same problem with the Puma. What we did was to approach at the normal low winching height, toss out the winchman and we would climb as the W/O kept him at the same height over the sea. We would then arrive at about 80 ft or so. After the pickup we would pull them up 20 ft. and descend as the W/O winched them in. I believe that a similar procedure was use for a cliff rescue.
It's all to guard against a cable breaking with somebody on it. I thought for a moment that with a dual winch you had a main and backup cable but it didn't look as if there was more than one. I can only assume that there is an awful lot of trust in the winch cable.
Not that I should worry too much, I'm not in the game anymore.