That's a great suggestion for using the gps to project a point so I can see VMG.
As for sufficiently easing sails downwind, one thing that has me probably tending to err on the side of overtrimmed is the way the main starts getting mashed up against the raked-back spreaders when it is out more than halfway. I've been worried about chafe.
Better yet, set up a Global Regatta course for your area (unless there already is one). Racing on our short course in Lake Travis has really helped me learn quite a bit in a short time.
Global Big Freakin' Regatta. Possible?
Lots of fun. But I need to sail faster if I'm going to catch those Chessie dudes.