Let us stay with US Standard units
12M = 39.3701 FT, part of the problem actually. Most of the world uses metric so if they set their machines to 12.20 m you get a shade over 40 ft. I measure twice, cut once whether it is a set or off of a reel.
I had ample string for my 16 x 20 110, with about 3 ft of tails.
GAMMA 4000 + WISE | PRINCE SPEEDPORT GOLD