Since the OP specifically asked about from a hovering helicopter, I've done this on numerous occasions, but never with a static line.
The jumpers specifically wanted a hover (below 10kias would do, really) because that gives them no airflow and therefore no stability until they pick up at 32ft/sec. Apparently it gives a totally different aspect to the jump, I guess akin to a balloon departure? But with a static line this 'buzz' would be virtually non-existent since the line and rapid deployment of the chute would give a quick stabilisation to the event.
Usual stuff about ensuring they depart evenly from both sides, step off and don't push off the fuselage, etc. As with other comments the length of the static line must be short enough not to create a problem, and a jumpmaster becomes essential to retrieve the static lines thus dictating a helicopter cabin size dependent on the number leaving and the number remaining.