I do think you can substitute the paste for powder, obviously adapting for the water content - if you need dry material, have to dry the paste. If you need a certain non-dry consistency, add less water than you would for powder because there's already some in it.
I don't think there's a way of knowing what yield to expect from a paste unless you know the potency of the starting material and how much the mass was reduced in making the paste. Or of course if the paste comes with lab results
