I've sailed Sonnets. They are great boats in strong breeze. Playing the sheet off the boom is not really done and will only work in light stuff. The cleat you've put on the boom may seem convenient but it's going to take your head off if you catch it on a gybe. As Tink said get a ratchet block I would change out the fairlead on the Center board case for a swiveling ratchet block and double up on the bridle end for extra purchase. Fold the tiller backward while tacking.