Only did a few banner tows in a C172. Would takeoff with hook held in left hand with right hand for throttle and controls. Of course with near full power always required, just tighten the throttle friction and leave it that way for takeoff. Then drop the hook. Oil temp would sit on the redline.
Flew over a flea market advertising for a nearby store, so the flea market owner called the feds to try to get me a violation. Was able to talk my way out of the investigation.
By coincidence I was visiting an airport out here in California today that had a big hangar owned by a large banner tow company with planes across America. They have super Cubs. One of them has a 6 cylinder engine. The Cubs have extended wings and vortex generators along not only the leading edge but also just in front of the ailerons. Plus some small wing fences.