[Propeller Ads] When to isolate a zone

Hi folks, I've just joined the forums and started my first campaign.

I've started two campaigns (One Smartlink and another MVAS campaign)

I've noticed that a single zone is bringing in conversions for both the Smartlink and custom MVAS campaign.

Having said that, is one zone enough to be taken and isolated in a single campaign, or should we wait for more converting zones before lumping them together into a separate campaign?

And also once we isolate these zones should we switch the target to Target CPA? (Currently