Bruce, I don't totally agree with that. If you were to ZR first and then add sandable primers and bondo etc, you are opening up lots of chances of incompatibility.
If however you were to epoxy prime over the ZR, you would give it a inert barrier between the ZR and all the other products. It might be a good idea, IMO. Also, epoxy primer has excellent adhesion qualities and might cause less trouble over the ZR than the other products would.
