I am not sure this problem can be solved by a full reset of the ST-16. Calibration maybe, but not a full reset...
Willie, have you checked the stick response in the channel settings ? That is a more accurate display of what is going on than the hardware monitor. Go into the channel settings for Rudder, hit the red button for that (I wanna say J4 ?), and then play with it for a full 5 minutes to ascertain whether the monitor matches your movements. If there is any drag or inconsistency, or things don't reach extents, then in all likelihood the stick needs a clean, which you should do with plastic-safe electrical contact cleaner.
If you play for 5 minutes and that control responds exactly as you input, then I'm pretty much out of ideas, because the sticks are the only part of that input / output system we can get to and control !