Hellbender,
You don't change your pressure to match your tubing ID and length. It's the other way around. You decide how carbonated you want your beer and based on the temp of the fridge you set the pressure to get you there. Once you know the pressure, you size your tubing so it doesn't dispense foam or dribble out. This can be anything between 3-10 feet. So, you probably wonder how you go about changing the tubing length all the time. You don't have to, if you make it too long, it just pours a little slow. If you make it too short you get a cup of foam. What's wrong with a slow pour? Nothing. 10 feet it is. It works great from 10-20i (that's an English Bitter up to a Wheat for me)