hueyracer - your technique has so many variables that it cannot be reccommended. 10% torque in hand does not equate to a 10% thrust margin which is a sensible performance level to keep when operating into CAs. Use your performance graphs to calculate OGE hover, anything else is guesswork. Unless your RFM has a graph for level flight performance at a specific speed that can then be equated to a power margin for landing, then the OGE graph is the only way and, as suggested earlier, taking 10% from the calculated max AUM will give you sufficent performance to deal with light turbulence/windshear etc.