Using the fuselage as a lifting body will allow it to provide some of the lift during cruise.
The lift that it provides (1/10th to 1/3rd of the weight ??) will reduce the lift required from the rotors and this should reduce the rotor induced vibrations.
The lifting body will partially serve the same function of the wings on a compound helicopter, except the lifting body does not entail additional weight and it will not significantly interfere with the thrust of the rotors.
This means that more power can go to the propeller and less to the rotors. This may also be closer to the optimum power distribution.
Twin booms at tail to clear propeller.
The booms will have a NACA0033 or NACA 0050 X-section. The so-called leading edge of the NACA airfoil will point straight up.
Consider having the complete lower surface removable, since it is basically a large single curvature. Start carving out the foam. The lower surface can be a thin sheet and the the sheet can be built up into a double curvature, then a fiberglass shell prodiced.
