Fortigate election for a new site

Hey everyone,

We’re getting ready to deploy a new site and I’m looking for some guidance on choosing the right FortiGate model.

Environment details:

~300 users

8 FortiSwitches over FortiLink

Planning to enable SSL Deep Inspection

Using full security profiles (IPS, AV, App Control, Web Filter, etc.)

Average traffic mix: Office 365, web browsing, VPN, internal apps

Average of 25,000–30,000 concurrent sessions

I know deep inspection significantly reduces throughput, so I want to size the appliance properly to avoid bottlenecks once everything goes live.

For anyone who has deployed FortiGate models in similar environments, which model would you recommend?

Any real‑world performance insights or warnings are also appreciated!

Thanks!