Best Practice & Recommendation in migrating EV VaultStore before EV 10 upgrade ?

Hi people,

Before Upgradingto EV 10, My company already purchased EMC DataDomain and have provisioned 40 TB of CIFS share to use.

I have EV 9.0.4 which currently running all of the 22 TB EV VaultStore on top of Block Storage as 20 Windows NTFS drives, so I've been using almost every single alphabet letters :-)

1. What would be the correct sizing for the CIFS share for the entire 22 TB VaultStore ?
2. How can I migrate all of the VaultStore to the CIFS share without affecting users / eg. downtime ?
3. The index must stay in the block sotrage or in the existing Windows NTFS drive, is that the case or can it be migrated as well to CIFS share ?

Any kind of assistance and comment would be greatly appreciated.

Thanks