Every catamaran haves a val slot off the sail, to give the barberhauler the best effect within the sail(mainsail and jib). A catamaran cant sail with a smaller sail(reef), but in the case off heavey breeze you could trim the sails to have less pressure in it! Always hois mainsail and jib fully!!
Im sorry, the only catamaran wich could sail with smaller main is a 'Dart Sting'(15feet FUB cat.), only the cat werent aiming on high selling. Acatamaran cannot be reefed, ONLY is trimmed proper too sail surcomstance at the time... Sail simulator has add the most common and most important trims, from sailtrims too crewtrims & steeringtrims... ONLY; the spi.sheet for crew is rather diffecult too manage. If you want too make a quick luff when sailing downwind with spi. im searching a easy/good way too make a luff while crew let go off sheet... When steering leech again a quick sheetpull(quick_automatic) is more realistic:):):)