Eric,

There's no place to learn like on the race course. You'll at least see how high you can point and how fast you can go down wind relative to other boats, which will give you a data point to start tweaking.

Your Portsmouth numbers are pretty close to where we split the fleet. If you're going to sail as a Taipan 4.9 Uni (no spi) you'll be in Division 2, otherwise Division 1. As Div 2 starts behind Div 1 you'll always have someone to run with, even if the big boats leave you behind. Just don't let the Sea Sprays beat you across the line - I did a couple of times last year and never heard the end of it :-))

I'm pretty overpowered for Rio Vista, so you should be able to kick my butt, at least on the upwind leg.

Pete