I'm using 3.0 KPa. I tried different pressures from 2.5 to 4 KPa:
2.5 KPa - very comfortable, especially off-road, it's harder to turn, and you start hitting the rim on the big curbs or when you jump
3.0 - optimal for my weight (85kg + 5kg equip + 17kg wheel)
3.5 - less comfortable, a bit wobbly on cracks and between cobble stones etc, very easy to turn and you can jump even from 30 cm sidewalks
4.0 - my knees start to hurt after long trips, very wobbly, you can easily make a 180 degree turn on the spot.
My tire is different from yours, and its recommended max pressure is 3.1 KPa: