When you wrap you chenille lay it half over on to the previous wrap. That is to say look at the chenille find the string that run through the middle as you wrap half of the fuzz will lay upon the previous wrap. this means the center strings of the wrap will almost be touching one another. Gives a fatter body. The amount of feather used can roughly be determined like this I/4 0z. jig about the dia. of a bic ink pin when pinched and cut. reduce the amount by 25% each time you go down a jig size. This will get you in the ball park . With practice you will be able to refine it more.