When setting up TrueSSO in a Cloud Pod Architecture, the best way is to have two Enrollment Servers deployed per PoD.
One single Enrollment Server supports 10,000 sessions and the better alternative scenario is to have a second server as HA (N+1).
You can see some great information under TechZone (link below), which have a reference architecture in a Multi-Site Architecture.
https://techzone.vmware.com/resource/workspace-one-and-horizon-reference-architecture#Multi-si
Thiago Valcesia
Senior Solution Engineer, EUC | VCIX – DTM | Office of the CTO, Ambassador