Do not launch an A class catamaran singlehandedly in an area with 10 knots ONSHORE breeze. Bad things will happen.
Boat easily tips in strong breeze on land seesawing on beech rollers when manoeuvring. Get those beach rollers back to the bow when done asap.
When stepping / raising the mast on an A class catamaran, tie one trapeze line to the rear beam as a backstay until the side stays are in to prevent the mast from swinging sideways and then forward. Use the other trapeze line with your trapeze harness to tension the side stays.