I'm afraid there is no simple answer.
To give a good advice one should to do a site survey. This will take into account the distance between the locations, structure of walls and ceilings, number of clients devices, kind of usage by client devices, uplink speed, etc etc...
Just one more option: if the APs could reach each other using meshing, and you don't want a ZoneDirector on site, you could perhaps rent space in a ZoneDirector in the cloud. This would mean that the ZoneDirector is somebody else's at a different location, and the AP's will use that ZoneDirector to be able to do meshing.
I could set this up for you as a test so you'll get an idea what that will be like, if you are interested. I have some room in one of my ZDs. That will work with the 4 zf7341 APs you have.