Hi ya everyone. This is not only for A320, but all aircraft capable of reverse thrust and applies to Saitek throttle quad. There is a way to get the engines to go full reverse without having to toggle reverse and then pushing the throttle forward again. This is a method that is all done in the sim control options.
Set the switch at the very bottom of throttle travel on the saitek throttle quad throttle lever to hold reverse thrust. This will keep reverse engaged as long as the lever is all the way down on the switch. Next assign decrease throttle to the same switch at the bottom of throttle lever travel (yes you can assign two actions to one switch). When the switch is engaged by the throttle lever reverse activates and stays activated and at the same time the decrease throttle will spool up the engines which are in reverse. Push the throttle lever forward and the reverse disengages. Ole school reverse, pull the throttle down and leave it there until you have slowed to taxi speed. Hope this helps someone.