It depends heavily on how heavy handed you are. My Dad is older and slower so it actually makes him smoother, where my brother in law is a bit heavy handed. Dad uses the default slider setting, and my brother in law drops most of his sliders low to slow his input down.
I use pedals so it a lot different.
A great way to check is to go into the TA and hook up with Morph. He has a screen the size of a house. He'll follow you around and see what controls are twitching and need smoothing out. Other than that it is going to be trial and error. Start at the default and move them down to slow, up to speed it up.
It's not quite the size of a house and infact if I can convince SWMBO to let me I plan on getting something even bigger!
Something I tell players is to go offline,select planeammomulti and change it to 10 so you have 10 times the ammo available,then bring up the target and shoot at it. It's best to use a plane with central mounted guns,like the P38 or the 109's. If you shoot enough bullets you will see a pattern develope,if it's side to side your rudder is giving inputs when you're shooting. If the pattern appears up and down then it's the elevator that giving inputs while shooting,you could also have both affecting your shooting.
If you find the rudder is the biggest problem,start by adding some deadpan,this will increase center of the stick and may be enough to reduce that unwanted inputs. You may need to add some dampening as well and if you are really heavy handed you might have to do as Fugi's brother inlaw and adjust the scaling.
What you are trying to do is stop the intial inputs on the rudder and/or elevator to stop any nose bounce. A little movement from the tail makes alot of movement of the guns so you want your stick smooth around the centering of the axii.
YMMV.
PS: my screen is 55 inches.....hardly big as a house! I need it because I cant see close in,a 24 inch widescreen make me legally blind!