[DStJohn]

Kiwi,
Yes you are on the right track, you can do it by offsetting the blade grip linkages. Vario rotor heads can be offset by +/- 45 degrees by moving the anti-rotation pin on the swash (I can provide photos if you wish).
The biggest thing to be aware of is that the multiblade heads want to balloon in forward flight. I am flying the newer 2 blade bolt Vario multiblade heads (3 and 4 blade) and it does not have a real strong tendency, so I am able to mix it out in my 10X radio. It can be done without the Helitronix mixer and gyros, it just takes some work & experimentation, which if your making your own head, you are up to.