DLO solution design

Dear Gurus,

      in need some assistance in designing a DLO environment from both server and storage specs. for the below customer environment. 

• Total number of users: 1000 (800 in site 1 and 200 in branch office)
• Data per user: 200 GB
• Percentage of PST data is 20% of actual data

i would really appreciate your assistance with this.

Best Regards,

Ahmed Saleh