multiple vcenters or single vcenter

I have a vcenter with single sso that have multiple datacenters added.

Then I have installed another vcenter in a different location and added a colocation datacenter to that new vcenter

then I added the 2 vcenter together using linked mode.

Both vcenters have their own sso

moving forward, if I add a new DC location, should i put it in vcenter 1 or 2?

Do I need mutisite sso? or is it better to split ssos

thanks