I don’t have Zebra (but I have a bunch of other soft synths and sample players etc.)
I am not aware of having an issue about installing too many “instances” of a synth if you use them in different rackspaces within GP.
Have you run into issue using Zebra (with different “sounds” selected) in multiple rackspaces? I would not think you would have an issue. (Caveat, others know more than me).
Zebra (from what I understand) is a true soft synth (not a rompler). So, the beauty is if you are specifically not using a rackspace with one of the “instances” (not sure if that’s the right word) it should not use CPU (and since it is not a rompler, ram should not be much of an issue).
Jeff
[PS I am sorry, I am probably missing something here. Feel free to delete this.]