5k potentiometer with 10 turns lock to lock for finer control: https://www.ebay.com/itm/183437985171

High current h-bridge to drive windscreen wiper motor directly from an RC servo motor control board which is then connected to the 5k 10 turn potentiometer: https://www.ebay.com/itm/Double-BTS7960B-DC-43A-Stepper-Motors-Driver-H-Bridge-PWM-For-Arduino-Smart-RCB9/193093897725?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Details regarding the circuit can be found here:

http://www.hessmer.org/blog/2013/12/28/ibt-2-h-bridge-with-arduino/

and here: 

(not my video)