• To minimize read-only time, I'd change the order a little.

    1. Full Backup

    2. Copy backup to new server & restore with NORECOVERY

    3. Set to read only

    4. Differential Backup

    5. Copy differential to new server, restore WITH RECOVERY

    6. Set to read/write.

    It doesn't make sense to restore the full & differential in one batch. You might as well just do a full backup & restore.