If the Zenith will be tying-up funds that would go to the AP if one were to surface during your ownership, then hold out for the AP. I say this, as then you don't have to wait for someone to buy your Zenith to permit you to buy the AP (as one of those ROs isn't going to hang around!)
If you have the reserves to cover the AP whilst owning the Zenith, then buy the Zenith and release at a later date when you have the AP.