Anyway, how do you guys and gals get the right amount for your size coil?
Like Heart says, depends on your coil ID.
I usually cut the coil into about 2" sections, long enough for anything I build and also long enough to be able to handle it, trim ends and so on.
Pull off of that strip a bit more than you think you need, and "roll" it between your fingers to compress it longitudinally. Twist one end (wetting can help) to feed through the coil. If it's too thick, pull it out and pull off a few strands, taper and try again.
As with any wick material, practice makes perfect