If you are speaking dynamic hair,you should not have too much trouble alternating between most of the figures simply by scaling the base object the dynamic hair is built on.You may not get a perfect fit(as each base is based on each figures unique mesh) however; with dynamic hair you dont necessarily need a perfect fit unless the hair is very short. The base object will either be transparent or not visible anway; its only purpose, is as a placeholder for the hair, so it can be scaled to inside your figures head if needed, the hair itself will still be visible.Obviously, you dont want the hairs base object bigger than your figures head or the hair wont look connected, but smaller is ok as long as you can get it close.FYI, most of the base objects I have seen have had "scalp" as part of the name which is a good practice for all hairmakers (IMHO)