Mary,

looking forward to hear what Rick has to say on the subject. Tried searching for any references to what Randy might have said, but did not find anything.

Timbo, I remember Bethwaite writing about peppering his sails with telltales in "High performance sailing", but dont remember exactly the context or results.
I agree with your aircraft wing analogy. A fuller main and a bit more mast rotation gives more power and drag, but gets you up on one hull earlier. But as we dont have a manual to sailshape, you need to know by feel and rough eyesight/experience where the limits are. I have read a lot of sailing and sailmaking books, and they all stop quite fast when they get into just what shapes are fast under which conditions. Bethwaite and Tom Whiddens book are the best I have found on the subject, but they are far from exhaustive (I guess you would need to write a book for every class of boat if it was to be meaningful).
I have found some advice I got from an old Tornado class olympian to be very good, and fast: "Put on more downhaul and mainsheet than you think you need, get your head out of the boat and go".