OK, guys, help me out here. I'm doing this Babbas Bed Sock, and it says to knit the foot until length desired, then begin the toe decreases. Well, how do I know the length of foot desired? Do you measure from the heel to the ball of the foot, or do you know if its a men's 11, you knit 8 inches then begin decreases or something like that from some set formula? Any help would be appreciated.