Would you have time to "test drive" or "audition" one or more skipper/instructors on some day trips before committing to spend a few weeks with someone? For a trip that long the personal aspects are critical.
Also, you could probably learn a whole lot about your boat starting with shorter sails with lots of maneuvering, docking, anchoring, traffic etc. as opposed to the long run to paradise where you might go for many hours at a stretch without needing to adjust trim.
Also, it might be easier for you to get your first "oopsies" with the new boat out of the way within a few hours of chandleries and repair shops. And, that would give you one or more captains' input and more time for your own ideas about how you'd like to improve and equip the boat for the big ocean run.