I am surprised that no-one has responded to your post as this is such an interesting question. I have a Bavaria 34 which we do not race, but i have spent many years racing on Impala’s and other well known designs.

If you can get sufficient tension on the main halyard to pull the draught forward in the mainsail, without the headboard comming up hard on the sheave at the masthead, i would not bother fitting a cunningham. It will flatten the bottom of the mainsail, but in the strength of wind at which you are likely to need this you probably need a reef anyway. and the lower fullbatten will as you say, reduce the effect of the cunningham.

Rigging a spinnaker involves a lot of personal decisions, the first of which is how the pole will be handled in a spinnaker gybe. Will the pole be dipped behind the forestay or will it be end for end, (mast end unclipped to become new guy, old guy end then clipped to mast.)

End for end can be achieved with single sheet and guy, but dip pole requires doubling up with a lazy guy and a lazy sheet. This system is also simpler to use in strong conditions, when using end for end, as the lazy sheet can be taken to the mast and clipped into the spinnaker pole end immediatly it is released from the mast, because it is not under load.

The only disadvantage with the lazy guy and sheet is you have a lot of string arround the boat to keep tidy.

Regardless of which system you choose, you should fit barber haulers. Only the guy needs to be lead through these, the lazy sheet is rigged free as only the guy needs to be hauled down to control the pole.

The barber hauler is kept hauled in on the old guy, until the new guy is established and hauled down. This keeps the spinnaker sheets within reach of the bowman until the gybe is complete.

When running in strong winds, it is a good idea to use both guys to control the spinnaker and to haul down on port and starboard to keep the spinnaker under control. This should not be overdone as the spinnaker needs to lift the bow of the boat to stop it ploughing into the back of the wave ahead, and the boat is more likely to surf with the spinnaker flown high.

Hope this helps