I recommend candidates allocate a block of of two and a half hours for the "event"
Of course this covers the briefing, preparation, the test, debrief and paperwork.
In my experience quoting a generous block time is quite important so people aren`t itching to get back to work/home/pub thus adding a self imposed time pressure.
Most candidates should have been briefed on procedure and had some local "simulator" practice with their FI or ground school instructor beforehand.
30 to 40 minutes is typical for the route.