Re: Dexterity and max block
I'm not sure if this is what you were asking, but every character's max block is 75%. You can see what your current block % is by hovering your mouse over the defense block on your character screen. As far as I know, the LCS is accurate on the listed block %... at least I've never read otherwise.
How many points of dex to achieve 75% block differs a bit based on character level and block % on the shield you're using, so there's not one easy answer, unfortunately. It's not too tough to calculate, though, especially with the links given above.