I booked the premium seats for my 4-ppl family. They just arranged a 5.5 seats cars with other 2 costumers for us. Why I said 5.5 seats? Cuz my hub sat beside the driver in front, the two other customers sat in the premiere middle 2 seats, my 2 youth kids sat in the side seats in the back, so I kept sitting the gap seat with borders in more than 1 hour. And the servive provider said they just followed the rules.
Please book the trip considering the travel situation. If in peek season, it may not be so satisfying.
But for the sight visiting, the experience was fantastic, the guide Dandan did a great job. Through we didn't met the Proboscis Monkey, we met some normal monkeys, fireflies, and fabulous sunset.
For the visit arrangement, it was perfect.