No one knows the exact crit strike formula as far as I know. People used to think that 1 CS = 2 Dex but that has since proven to be inaccurate. Needless to say though, +10 crit strike will help you a whole lot more than +1
I don't think anyone will be able to give you a clear and concise answer, but if you read arxyn's guides you might get a better idea.