Downwind have someone ready to release the vang in case of a round-up knock-down or anytime the boom hits the water. You might twing on spin sheets or knock them down to the deck with snatch blocks. Grinder should be ready to over trim to prevent death rolling. Good idea to use those rope clutches for the spin halyard as mast cam cleats might not handle the load.

How do you trim a spinnaker when it is blowing above 30? LOL