I am new in this community, we are planning to bring Netflow on board so please help me for the below listed quereis

We have almost more than 65 - 75 remote locations, and we are expecting to receive traffic 350 - 400 interfaces with Addon on IPSLA, NBAR & CBQOR

1. Shall we deploy the Netflow as standalone or we can deploy with Opmanager ?
2. Will it be better to deploy on Windows Server or Linux Server ?
3. If we use Windows server which database is recommended MYSQL OR MSSQL ?
4. How we can calculate the flows per second ?

Adnan