How much pressure should I use to push a stout when I have 75 percent nitrogen and 25 percent co2 and the are in side the keezer temp is at 35 degrees.
There are good calculators to help determine stuff like this. Nitro faucets tend to be happiest in the 25-40psi range, and tend to foam badly when the carb level gets over ~1.8 vol. If you carb your beer under 1.8 vol and the calculator tells you that you need a pressure outside of the above range, you should consider a different gas blend or serving temperature. The gas you're using (G-mix) is intended for serving at 1.2 vol, ~34°F, and 30 psi. For higher carb levels you'll likely want a gas blend with more CO2.