reno:
Nice find.
Yes, frustration on 'short' spools & bad guesses have been made by most, if not all of us. Even the supply house guys could 'goof' on length of ordered cuts. Frustrating and a great $$$ waste.
When we had questionable LOL (length of leftovers) on #2 and larger, a 'close' educated guess was a DMM and the resistance chart, and a calculator.
