Ok maybe some things to help you #15 AWG is 101.44 feet per pound.
So next you're making coils 2 inches in diameter. C= pi x diameter. circumference =6.283 x 40 x4 =1005.309 / 12 83.77 per coil x 12 = 1005.3096 / 101.44 = 9.91 pounds..
But I'd add in a 10% fudge factor at least so add another bit and I'd say 11 lbs would do it.