Sizing Tool for Messaging Gateway Virtual Appliance

Hi everyone,

How do we size Messaging Gateway based on the number of users and mailbox for Virtual Appliance?

As I know Symantec has a sizing tool but I can't seem to find it anywhere. (including the partnernet etc)

Please advise if anyone has it?

I need it for a hyper-v environment. The article I checked does not state how many users/mailbox it can support based on the requirement given.

Thank you.