Get some 3X5 cards, and fill out one for each string you make with the following information:
String for: 64" Bob Lee Legacy
8" and 9 1/2" tag ends for 2" and 3" string loops
Use position 19" (varies depending on your string jig)
12 strands of BCY 10 padded with 4 strands of same
Serving: Halo Beiter .021
I fill this out as I'm making the string, and sometimes have to go back and change things after I finish. For example, as I recall I initially set the string jig on 19 1/8" and had to put more twists in the string than I liked, so changed my directions for future strings to 19". For my jig, whatever I change on the jig has 4X the effect on the final string, so when I changed the jig 1/8" storter, the final string would be 1/2" shorter.
Later, if I have another 64" recurve I need a string for, I can try the Bob Lee string. If it is too long, I use a shorter setting on the string jig, and vice versa. That way, each string you make gets you closer on the next one. Of course, if I need a string for a 68" longbow and I've never made one for a 68" longbow before, my first try might not be as close as I would like.
Actually, I really don't know what serving is on my Bieter Winder, because I obliterated the label when I put it on. I think it was .021 Halo, but I'm not sure. Note to self: next time you replace serving spool, make a note of what kind of serving you replace it with.