Originally Posted by moosp
...I seek the expert advice of the pprune design team...
Hehehe. It may be that simple, Moosp. Then again that jet output looks about the same height as the machine CG, so the extra thrust likely just reduces nose below horizon attitude. If cyclic control was a problem, i would have thought RHC would go the usual route of putting additional horizontal empennages on the tail boom. Don't forget the RR300 will raise the CG over the Lycoming O-540 engine.
I think it's just to try and keep the machine competetive against machines like EC120, without the cost of a bearingless 3-blade rotor. It just keeps a good moment arm above the CG.