Hardware specification for replace old system

Hello guys,

I’m to make a proposal to a customer to replace his old scada system. They have almost 200 plc in the plant and 120 of them are identicals.

It’s 35000 tags (screen refresh rate is 250ms), 7000 trends (at 1s) and 15000 alarms (at 500ms).

Today they run this system with eight servers (machines with almost 10 years old), I thinking to propose two Ignition servers maybe in a virtualized system.

Any tips?