I'm not sure if the mixture would work the same, but if what you are already using works for you then I wouldn't change it.
Depending on who the supplier is depends on what they consider fine pine bark. We use the 3/4" -1" fines like here
http://elixsonwoodproducts.com... which is about the size of a dime. It's nothing but pine bark (no other part of the tree)
Some places consider fines the ground up pine bark that looks like coffee grounds basically.
