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Hair is hair and can be used across any figure.

To fit a hair to a figure it wasn't made for, simply rescale using the XYZ and Scale dials, and if needed move it using the XYZ Trans.

That's true.

True, it generally works on most figures. However, I've tried doing tha with some of the hair props  from James, etc. and it didn't sit too well on his head (I'm using the Mil char David.)
 
Thanks for the tips though! I'll have to remember that when I do try it.