Sizing help — university internet edge, 3 Gbps today, 4,000–5,000 students, 7-year lifespan. PA-3430 / PA-3440 / PA-5410?

[simsim]

Looking for sizing advice from anyone running PAN at a university/campus internet edge.

Environment:

• University with 4,000–5,000 students plus staff/faculty
• Current internet bandwidth: 3 Gbps — expect this to grow substantially over the appliance's life (bandwidth per student keeps climbing; wouldn't be surprised to hit 8–10 Gbps by end of life)
• Firewall lifespan target: 7 years
• Role: internet edge only — no east-west (core switches handle inter-VLAN)
• Planned security stack: Threat Prevention, Advanced URL Filtering, DNS Security, WildFire
• SSL Forward Proxy on managed devices (~70–80% of traffic decrypted; BYOD/student devices get certificate inspection or bypass)
• DMZ with published services (web, LMS)
• LAN side: 2x 10G LACP to core, so ports aren't the issue

Where I'm stuck: datasheets show Threat Prevention throughput (PA-3430 = 10.5, PA-3440 = 12.8, PA-5410 = 35 Gbps appmix) but no decryption figures. I've read decryption cuts effective throughput 60–70%, which would make the 3400 series marginal by mid-life if traffic grows as expected.

Questions:

1. For this profile over 7 years, what would you deploy — PA-3440 or PA-5410? Is the 3430 out of the question?
2. What's the realistic decrypted throughput people see on the 3440 vs the 5410 (with its hardware SSL acceleration)?
3. For those at universities: what decryption percentage do you actually achieve with a large BYOD population, once QUIC and pinned apps are accounted for?
4. Any experience with how appmix numbers translate to real campus traffic (heavy streaming/CDN, thousands of concurrent users)?
5. Sessions: with 5,000+ concurrent users, is the 3440's 3M session cap comfortable, or have campuses hit session/CPS limits before throughput limits?

Evaluating against FortiGate 701G and Check Point 9700/9800 quotes, so trying to identify PAN's genuinely right-sized model rather than the cheapest one that passes on paper.