Well from my point of view you're into the clouds here
When I was developing an MD900 I asked around all the Heli designers I knew & my eventual semi solution was to get several heli's with desirable characteristics - open their Air files in AirEd & copy out the relevant sections & paste. You will find - if you are using the B206 as a base - there are several variables not even included in that air file which others have managed to develop (or copy from other fixed wing aircraft & graft in)which can also make a big difference to handling & performance. ;D
It would be interesting to hear how you get on. What heli is it?
Simplicity is the ultimate sophistication. – Leonardo da Vinci