well i fly r22s and am only 10 and a half stone.
keep 70 knots , the little extra airspeed helps recover to 110% at the end your rrpm shouldnt go below 90%, low i know but it is acceceptable if the rrpm persists in dropping after 90 % you should recover the problem may be in the rigging, talk to an engineer and he should be able to add a more negative pitch when collective is down , the collective will have a higher position in normal flight.
other option is to bring weights with you but if and when you do have a real engine failure( i have had 2 so far) you need to be able to handle the helicopter with just you, and god help you if you are light on fuel at the time as less weight
= less rrpm
[This message has been edited by whatsarunway (edited 18 October 2000).]