I'll bite Ian

I suspect that keeping the wing off the ground with aileron in the
initial part of the ground run works because with the tailwheel/ skid
on the deck the effects of adverse yaw & secondary effect roll are
negated.

There is no way on Gods earth that the rudder of the Nimbus is going to
accelerate a dropping wing at the beginning of the ground run.
Personally I thing the rudder of the
Nimbus is there because us pilot types wouldnt but an hairyplane
without one

Ian