Our Core Wool Batting is my personal choice for fast shaping and needle felting of the core body parts for all of my Felt Alive dolls. It is used for core needle felted parts because it is a rather dull, natural white and has a bit of straw and grass in it (vm or vegetable matter) which will be hidden by the outer layer dyed wool. Of course it can be used to felt anything you want as it is a great all-purpose needle felting wool.
I typically use core wool for any project larger than 8" tall. For smaller projects I usually sculpt all the parts out of the dyed wool of my choice and skip the core wool as it can be tedious covering small felted core wool projects with dyed wool.
How much core wool do I need?
It really depends on your felting style or how densely you felt. For me, I typically use about 2 oz of core wool to make all the core body parts for a sturdy 12" needle felted doll.