In Aces High, esc to pull up clipboard, setup, controls, joystick, settings.
If pitch & roll are ok leave them be for now.
Upper left hand corner is a scroll bar, change to rudder.
First check out the deadband. Deadband sets where the input starts. If your rudder is very sensitive in the middle this may be one way to tone it down a bit. Raise the slider say half an inch, then try it.
Better? Good enough? or need more?
Damping reduces input overall, if rudder is still twitchy try raising damping. No more than 1/4 of the total possible.
OK now? Still touchy?
Sliders.
The sliders on the left are a visual representation of a control input sliced into 10 pieces. Slider at the bottom = no input at all. Slider at the top = Max possible input.
You may want to lower these if your rudder is still very sensitive.
You still want to end up with the last slider all the way to the top.
But instead of the default stairstep, put in a very slow gradual climb
So the first 5 or 6 sliders would barely inch up, about 60 or 70 you'll need to step up in BIG steps to reach the top at 90.
How is it now?
Hopefully one or all of these will have tamed your monster.
Let me know if you have questions, problems or need assistance.