I'm about 185lbs and run my 29er HT at 30psi on trails with tubes. 2.2" tires.

On pavement I'll put them up to 40psi. Every year when I get back to trail riding, my friend will chide me about my pressures being to high. I'll say they aren't, but he's always right

Trust me that you will be faster if you drop your pressures down slightly. Pump them up to your 40psi, but once on the trail try bleeding them down gradually.

The best way for me to judge good tire pressure is on hard cornering, and ruts. Too high of pressure will cause your front to feel unsure, and your back will be bouncing.

Drop your front pressure by doing a couple taps on the valve to burp air. Then take some corners and repeat. This should start to make the front feel very sure of itself, you feel it grab predictably - keep your eyes past the apex of the turn, not down at the tire.

Drop your rear until the thumps become "dulled".

It's in your mind that the tires feel "flat", trust me I was the same way, doing far more road riding then mtb. It's incredible to realize your mtb speed will increase, because you'll have more shure footing and less bounce that will translate into less speed loss in corners and rough terrain.

Running tubless you have nothing to worry about when it comes to low pressures, unless you go crazy low like 12psi, which you'll know