@iarita not sure what you mean. You're going to need various lengths of string for alphas. So your base string should be the length you expect the full design to be, and for the rest you have two options. Either you dont cut the particular colour of string from the skein, but instead use it for all the knots and then tie it off, or you use a length youre comfortable working with and if its not enough just tie it off and feed some more in.
Word of advice though, I would first make a simpler alpha patterns with fewer strings before you attempt this one. Its fairly small but it does have a good number of colour swaps that can make it tricky for a first try. Happy knotting!
