Just to follow up on this thread now that I've used it in anger.
In the end I preferred the solution based on a sequence of logical switches, the reason being that it allows the reduction in rudder rate to be set as a percentage regardless of any exponential or dual rates that may or may not be switched in.
It works better with the logical switches arranged so that, for example, as the throttle is opened from idle:
All switches off
L1 on, rudder mixed with rudder at -50%
L1 and L2 on, rudder mixed with rudder at -(50% + 5%)
L1 and L2 and L3 on, rudder mixed with rudder at -(50% + 5% + 5%)
etc.
The reason for this is that delay can be added to smooth the transitions somewhat. But if the switches are arranged:
All switches off
L1 on only, rudder mixed with rudder at -50%
L2 on only, rudder mixed with rudder at -55%
L3 on only, rudder mixed with rudder at -60%
etc.
the delay function causes some very strange behaviour at transitions.
Cheers,
A