mr Vfr man,
regarding downwind takeoffs in a Robbie, a good rule of thumb is that if you have 2" in hand in the hover from your 5 minute rating then you should be able to do it safely(however if the engine fails in the early climbout, things are looking v.bad)
also I agree with heloteacher about the 206, if you have got 4 heavy punters in it as well as you then you have to be real careful to keep torque below 100% while hover taxying.
if you want a bit of power then try a super puma, they really have got power
stay lucky