It also kind of depends on how many instances each have in comparison.... but there are also other factors like all the upgrades they did. Or how you can't store KIs so people can't spam. Or how you can't go in solo and in fact it's highly encouraged to bring decent sized groups etc. I don't really see congestion issues but that's largely because I doubt there will be more than a couple of groups going at once. Especially once cp campaign starts lol