I'm not experienced as some on this forum with being an exhibitor etc., but I've been to a few shows including
Annapolis and
Miami. Both of these are head-and-shoulders above the regional shows, particularly if looking at sailboats. Even then, they do not always get all of the brands (particularly of note is
Catalina, which I guess is sick of selling yachts?). You should check the websites, where they post their committed vendors months in advance. You sound like you've planned out this
purchase in advance (great), so you'll be less likely to be taken in by some slick sales talk by
charter companies telling you to sign-on-the-line and they'll pay you for the honor of owning a
boat.
The two major shows are much like their towns -
Miami is big and glitzy, Annapolis is like a small town. Both have 'preview' days on the first day (usually Thursday) which I really liked. The tickets are about $20 higher for first-day, but this is nothing compared to your other travel costs, and the crowds are much less. You don't wait in as many lines to get on-board the popular boats, and the sales people are still friendly. Like any major event, go in with a plan for stuff you must see, nice-to-see, and a couple hours of wandering around the booths.