Willpower, Same as FormulaNova, seat harness, in preference to a waist harness. The bloody waist things always ride up.

Maybe a waist if you dedicate to waves only.
From Guy Cribb school, his thoughts on hooking in and feet in, was this should be within the first 20 meters, get the hook in, then the feet sharpish. Any further along and its slack sailing he thought.

You ask about life vest, the NP high hook is not to bad a vest, compact and takes the chill out with the padding in the front. Some wont wear a vest at all.
My initial was not too as well, but late 2008/9 a windsurfer lost his life in Northern NSW or Southern Queensland when he was caught in an outgoing tide and huge rollers coming in. No vest and ran out of steam when he became separated from his gear. Promised family I would always wear a vest from then on.

Makes waterstarting a lot easier as well.