NWTF Guidelines for their scoring system:
Step 2:
Measure each spur. Spurs must be measured along the outside center, from the point at which the spur protrudes from the scaled leg skin to the tip of the spur. Add both spur measurements and multiply the combined length of the spurs by 10. This is the number of points you receive for the turkey’s spurs.(http://i66.photobucket.com/albums/h248/gslam95/MeasureSpur-2.jpg)