This is a question to the experienced people who use to come at the opening night. How does the procedure looks when they open the festival at 18.00 and how long will it take to get in if you arrive the same evening maybe around 17.00.
Last time I went we arrived Sunday at noon and had to que about 1 hour to exchange our tickets for wristbands and then enter the festival.
The worry is that we will have to que for hours and get into the festival to late in the evening. We don’t care about getting the best places so arriving early on Sunday is excluded for that reason.
On opening night, they give temporary wristbands so the queue will not take that long of a time. I only have experience from last year, but at least the line in the entrance which led to P and J went really fast.