This is a great thread. I want to second what Matt is saying above, particularly with catamarans. Boatspeed and VMG can have a huge impact on my perception of a race as well as the shifts and tactics. And with catamarans in particular, different sailors can get significantly more or less out of the boat in terms of this boat speed and VMG. Life gets a lot easier if you can go fast.

We sailed an N20 and worked both sides of the course to good effect when we were sailing well. The classic land effects noted above were there, but people could do great by seeing what was going on ahead of them through other boats' point\speed\heel as well as breeze on the water.

BTW, I felt like the start line and course generally got more square over time.

And we often were surprised by the header on the final short beat to A.