Choosing bouyancy as best as I can

[jago25_98]

I'm looking for my next board but I want to get the buoyancy `just so`.

At the moment I have a 5'10 twin fish.
Sadly it is a little to short for my ability (about 6" or more), and it's also not particularly easy to duck dive. I feel this is because I weigh 11.5 stone, and I think 13+ stone would be better for it.

Where can I find boards rated by buoyancy? I can't go by size because, as I've learnt, size is not any guide to getting a match to the rider's weight.

What I'm after is something longer (6.5-7.5') and slightly less buoyant than what I have.