VDOM (Virtual Domains ) administration

We are currently checking how we can administrate VDOM for each customer. In our standard design, we need one @IP for

each VDOM, that mean we need 100 IPs for production and 10IPs maximum for Preproduction.

In which way could we used private IP for that administration ? Our concern is managing overlap with customer. How customer IP plan is managed ? If we give you one subnet, are you able to say us if we can use it for our administration ?