I will go out on a limb on this one.

Based on the test data I have seen (which is limited) the finish should be absolutely clean and fair, finished to 1600 grit or better.

The flow around catamaran hulls is laminar. The water touching the hulls does not move. Wax will not will not hurt anything. If the wax is thick enough to fair imperfections and strong enough to stay on it will help a little.

In simple terms

Touchup any scratches
Fair the hull, get rid of any bumps or hollows
Polish it until it's real shiny
Keep it CLEAN