@BacForKnot that's difficult to say for this pattern, at least for the strings of colour A. I'd say make these about 90cm long and if you notice one of them running out faster, just make a fb or bf knot between two black strings to switch them around. My estimate is that you need 82,5cm for B, 104,5cm for C, 104,5cm for D, 101,5cm for E, 107,5cm for F and 89cm for G.