Good news is that you have an O2 gauge, that makes tuning easy. Just imagine what a pain it was to have those old Holley DP carbs back in the 70's and 80's without O2 sensors.

Just lean out the main jets until the cruise AF is correct and then go from there.

When you tune a carb you start with the idle circuit and work your way to the power circuit.

I don't know why you changed the power valve. I'm thinking you might have gone the wrong way there. Do you have a vacuum gauge in the car? If so, you should watch it while you drive. Head up a long hill and see where the vacuum is when it needs more fuel.