I would not pretend to be very knowledgeable about centerboards since I have not even taken possession of my Bristol yet. In buying this boat I was not particularly worried about the centerboard arrangement since it is something that can be over-engineered pretty easily and Hood designs and later Bristol build quality are well-regarded. A consideration is having draft less than 5 feet on a 45 foot boat.
I have been told that there are three distinctly different uses for the board
1. going to windward in light to moderate conditions - I was told that it is a good idea not to use it when it is really blowing - not entirely sure when really blowing starts however.
2. to provide a convenient way to balance the helm in different conditions
3. to have a couple of feet of board down when creeping into really shallow water as an early warning system
Anyway, give me a year or two and I can give a better answer.