To Alouette
Haven't actually done any dropping myself, but once met a man that had,he said the big thing to watch out for is the c of g shift as they hop of the racks/landing gear(obviously the lateral moment if one side jumped before the other could make for an exciting time !)
But he said it was no great shakes( s long as you were ready for it).
He was using a jetbanger I think, the only special eqp was the hand loops for the jumpers ( he also pointed out that jumping out of helis was for experienced jumpers only ) I think he did his dropping in the states (based in UK now)
As I say this s second hand info.
Sorry cant be of more help
Regards
hoverbover