This is how the reverse thrust functions currently wrt Logitech TQ:
Option 1 (Not realistic, easy to use, guaranteed to work):
Control - TOGGLE THROTTLE THRUST REVERSER
Type - Button press and release
Action - Toggles the thrust modes between normal and reverse
Bind to - Press and hold buttons on the Throttle axes
Usage - In normal thrust mode, move levers forward (backward) on the axes to increase (decrease) thrust. To activate reverser mode, pull back the levers to the button positions and immediately reset to the 0% detent. Now you are in reverse thrust mode. Move levers forward to increase reverse thrust up to max. Move levers back to 0% to reduce reverse thrust. To revert to normal thrust mode, again pull back the levers to the button positions and immediately reset to the 0% detent.
Advantage - You can granularly control the amount of reverse thrust individually on multiple engines
Option 2 (Not realistic, difficult to use, guaranteed to work):
Control - HOLD THROTTLE THRUST REVERSER
Type - Button press and hold
Action - Activates reverse thrust mode for the duration of the button press
Bind to - Push and release button on the TQ except the after-detent buttons (e.g., use the T1 button)
Usage - In normal thrust mode, move levers forward (backward) on the axes to increase (decrease) thrust. To activate reverser mode, press and hold the button. Now you are in reverse thrust mode. While keeping the button pressed, move levers forward to increase reverse thrust up to max. Move levers back to 0% to reduce reverse thrust. To revert to normal thrust mode, release the button.
Advantage - You can granularly control the amount of reverse thrust individually on multiple engines, but it will take quite a bit of finger gymnastics to achieve it. Most undesirable option of all.
Option 3 (Realistic, easy to use, not guaranteed to work):
Control - DECREASE THROTTLE (or DECREASE THROTTLE X)
Type - Repeated button presses
Action - Moves the throttle control backwards by small amounts from any throttle position
Bind to - Press and hold buttons on the Throttle axes
Usage - In normal thrust mode, move levers forward (backward) on the axes to increase (decrease) thrust. To activate reversers and set them to max reverse thrust position, pull back the levers to the button positions and hold it there. What this does is repeatedly sends a decrease command which keeps decreasing the throttle position until it hits max reverse. Now comes the questionable part. To disengage reverse thrust and go to 0% idle thrust, move levers to the 0% detent position. This may or may not work depending on how noisy your potentiometer is. Ironically, worse the quality, better the result. I hope you are understanding the technical limitation of this implementation. When you pulled back the levers to the button, you sent a bunch of decrease commands, but when releasing the button and setting the lever to the detent position doesn’t send an ‘increase’ command to actually put it in the idle position. You are relying on the throttle axis getting sensed by the sim to make that happen. So, if you have a potentiometer that creates some noise at the 0% detent, then putting the lever there will make the axis active and disengage the reversers. If you have a clean potentiometer, you will find that it may not sense the axis once you set it to 0%. You have to move the levers a bit above 0% to make the axis active.
Disadvantage - You cannot granularly control the reversers.