Hard to explain, but you will eventually find a sweet spot. GVW, shocks and fork, tire size and brand, temperature will change it a bit. You can split hairs on tire pressure, but like Ian said, 35 works for him, 38 works for me.
Get 30 and lower and the front wobbles, get 45 and they feels like hard rocks and make a tiny footprint with no grab.
Get you a good accurate USA gauge too.
