I have a Helms 25 with a shallow fixed 1650# ballasted keel and a 6' long steel 300 pound centerboard. All good points above. I might add depending on the design of your boat, the amount the centerboard is lowered can be used to adjust your weather helm. Going close hauled, it's amazing how the tiller feel changes as the centerboard is lowered from zero to ten turns of the centerboard winch
. 30 turns is full down.