Plan festival set conflicts.
Every festival clash costs you exactly one act, since two simultaneous sets can only yield one. Halving the clash count and rounding up gives the acts you must drop. What is left still is not free: at twelve minutes a stage transfer, a dozen acts spend over two hours walking, which is the reason a schedule that looks feasible on paper collapses by mid-afternoon.
Acts after clashes
Acts you can see = acts wanted - ceiling(clashing acts / 2)
Time on site
On-site hours = (acts seen x average set length + (acts seen - 1) x stage walk) / 60
Sometimes, but the walk usually eats the second half. Splitting a clash generally means seeing two partial sets rather than one complete one, which many people regret.
Crowd density, one-way routes and bottlenecks at bridges or gates mean a distance that would take four minutes on an empty site routinely takes twelve to twenty at peak times.