I use a device called "safety trim".  Basically it controlls my elevator and aileron trim at two different speeds based on the input of a speed switch that I set at around 140 knots in my IV.  Also if the trim switch sticks, the device shuts down the output after three seconds so you cant have a runaway trim.   It has a reverse position that is allegedly suppose to return the trim back to the position it was in prior to the runaway but I have never used that.   probably overkill and not the cheapest solution but it works for me.