SCI uses the gross score with no deductions. Just take your b@c measurements for the main beam , g-1,g-2,g-3,g-4, and the four mass measurements add em up, them add the inside spread. What you get is your gross and also the sci total. So on your g-2 (back tine) you take the tine measurement divide it by 2 and thats where you take you circumfrance there. Did tha help?