Well you already have plenty of knowledge of the Sea - experience is FAR more important than anything else so just get out there and have fun and practice with some friends BEFORE you start taking out the paying passengers.
It would be a good idea to try to go out on a similar "thrill ride" type trip first to see what the other people are doing and just how far they push the boats with passengers on board.
These people post on here quite often - I am sure they could help if you asked them nicely - they have loads of experience.
Also try having a word with
Very experienced at building - and more importantly supporting such ventures and have sent boats all over the World.