October 2026 fall festival: 600 people, 8 hours. How many units?

I'm planning an October 2026 fall festival with 600 guests over 8 hours, on a grassy field with good truck access. There will be food vendors and beer tents, so I expect heavy usage, especially in the afternoon peak. I need to decide on unit types: standard portable toilets, deluxe flushing units, ADA-compliant units, or a restroom trailer. How many total units should I rent to avoid long lines, and what's the right mix for a mixed crowd with alcohol? Should I cluster them or spread them out near food and beer areas?