"Hull speed" is what it is. The only way to change it is to change the LWL. That does not mean, however, that you cannot get the boat to go faster. "Hull speed" is just a theoretical number. The boat may very well go faster, or slower, depending on a lot of variables.
That said, a boat like the Westsail, with a full keel
and deep, round bilges is going to be hard pressed to exceed its theoretical hull
speed. The CSY boats, with a flatter bottom, cutaway forefoot, and much more of a "fin" keel (though not a fin in the way, for instance, a J-Boat has a fin keel) is more likely to be able to exceed its theoretical hull
speed. So more sail might help there.
Now, having said THAT, there is yet another caveat. I've never sailed on a CSY. I don't know what they sail like. A lot of boats, if you put up too much canvas
, they heel way over and end up actually going slower than if you just sail them the way the designer
So, while this kind of research
is useful, don't get too hung up on the numbers and ratios. Good luck.
Edited: By the way, you might want to double-check your figure for motion comfort for the Westsail. By my calculations, you've got the right numbers for the CSY 33 and 37, but I come up with 39.95 for the Westail.