• You should format you shared disks with NTFS before you form you cluster. If not the disks will not be eligible as witness disks. (NTFS is a requirement for a disk witness.) Do not assign a drive letter or mount point to your witness disk. (Disks used e.g. for a clustered file server needs a drive letter assigned. Do this through Failover Cluster Manager.)
• If you want to run, say, a clustered file server, the corresponding role must be installed on the nodes of the cluster. This is true for all built-in roles.
  
• To be able to add a share to a clustered file server in Failover Cluster Manager; the Remote Volume Management firewall exception must be enabled on all nodes. To enable this exception from the command line:
  netsh advfirewall firewall set rule group=”Remote Volume Managmenet” new enable=yes
• To move the default cluster group (called Cluster Group by default) with PowerShell:
  Move-ClusterGroup –Name “Cluster Group” –Node <name of destination node>
• To see the owner of the default cluster group with PowerShell (the only way you can actually see that information, to my knowledge (except with cluster.exe, of course)):
  Get-ClusterGroup “Cluster Group”

Happy clustering!

Morgan