Here's how how it works for me:
I am arrow point on gold at 80yds and outer blue ring, Sight mark = 0 vert, 5 horizontal
I have shot all distances lower than this in 10yd steps having attached a linen tape measure to the outer face of my bow and using a black 'O' ring as a vertical sight pin with "zero mm commencing at the top border line of leather grip and bow.
All of the vertical marks were then entered in as sight marks - I.e. 60yds = 22mm, etc before the tape measure was removed to conform with any rules that might forbid stuff both recording thosestuck to a bow.
To set a given mark during a shoot I use my bracing height gauge to put the "O" ring where it needs to be.
Horzontal marks with
longbow are wholly wind dependant so I never bother recording those, instead I begin with the edge of the "O" ring kissing 3 o'clock black/white and adjust accordingly as the shoot goes on
Has worked really well for me this year so far
Karl