One of the most useful tweaks is properly understanding and setting up Washout Gain and Return.
This is yobuddy's overview: https://www.xsimulator.net/communit...s-in-the-washout-filter-do.12224/#post-159230
(Washout) Gain – This is how much we will react to changes in the input from the game. If your simulator is not moving enough from the output from the game, Increase this value.
(Washout) Return – This is how fast we try to return to zero after a movement has occurred. If your simulator is not homing (re-centering) fast enough after a movement, Increase this value.
The Washout Filter is needed when your DOF input fails to return to center after the force is applied to the Axis.
Example: when car's rear end slides out. The Axis is left in a non centered position. If the car then needs to slide out in the same direction again, there would be no room left for the needed travel. To overcome these circumstances, we use a washout filter as to slowly move the axis back to center without the rider’s knowledge of it occurring. A Gain of 1 or above must be used for the Washout system to be considered active. A setting of 50% for both Gain and Return is a good place to start for any game.
Here is @Spit40's succinct summary of how Gain and Return function, though please note the Smoothing settings are a bit too high in his example settings: https://www.xsimulator.net/community/threads/aerofly-fs-2-plugin.9096/page-6#post-135790
Washout Gain/Return (Updated and Corrected)
After many hours and some extra help from @yobuddy I now have a much better handle on washout gain/return and my flying feels a lot better. I really think its essential to use this properly with flight sim to get a good feeling. The problem is if you don't know quite what both gain & return do then pure experimentation can give very confusing results.
I'm mainly using this for banking mapped to the Extra2 roll/sec DOF. What I was after was a fairly responsive roll without being snatchy which would imperceptibly return to neutral once I had completed applying the roll, so that I feel the force of the roll taking effect but not the return axis movement. I'm also using it for yaw mapped to Extra3 yaw/sec. This is my current setting, though I may tweak it more now I know what's going on.
These are my main DOF mappings.
I'm finding 100% fine as I'm flying cessna's rather than fast jets, so no extreme combined DOFs.
This is the Extra2 setting.
Smoothing: I want it very smooth so 100%
Washout Gain: This determines how responsive SimTools is to the DOF input. 100% means very responsive. 1% means very unresponsive, which means changes to this DOF would have a very diluted impact. 0% means all washout functionality disabled. I'm not sure if 100% is what you get if washout is disabled, but I found 100% too snatchy for flying, in fact it seemed to undermine all that 100% smoothness. Settings around 75% seem to give the smooth responsiveness I was after when applying the roll.
Washout Return: This is all about the subtle return to neutral. Without it if I, for example, start banking to the right then hold the bank angle at 20 degrees what I feel is a strong banking force followed by an often stronger returning force once I reach 20 degrees. Very unnatural. Now once I reach 20 degrees and my roll acceleration returns to 0, the axis returns gently to neutral. It can feel a little gritty but I think I'm now hitting the limits of the motors & gearing and their ability to make smooth fine adjustments.