Rolf,

I think the uni's are advantaged in the light stuff around the course. The advantage in boatspeed and angle both up and downwind compensates enough for having only 2 hands.

In the medium and heavy wind I think the uni can still race fair upwind (Hans Klok was superfast upwind last race in Holland with 15-20 knots of wind).
In these conditions however the hoisting and retrieving takes too long for the unis. Once the spin is up, I think in 20+ a uni will still loose, in everything below I think you should be able to keep up. So getting a system to hoist and retrieve fast would make the biggest difference I think.

I have been talking about this at the worlds with some people and having a system where you can store energy during the race to 'auto' hoist or retrieve the spinnaker could be a solution.

Gill