If one does not wish to hold onto the steering, perhaps an Uber is called for? :hun:
I installed ISO grips on my Rally that have raised soft rubber pads, that are very comfortable. If I am on a long stretch of road and wish to rest my fingers, I simply leave my palm on those very soft pads and open my fingers. I still have the acceleration speed, control and can relax my finger grip. The palm is sufficient to hold the speed until I wish to slow down or speed up. I had a thumb screw rev set on my Harley that I tried once or twice and found it not to be very good, even though it allowed me to set the throttle just enough to hold it if I wished to take my hand off the bar. I could easily slow down with it, since the resistance was just enough to hold the speed I set it for. I still did not like the idea, so I did not use it after the first couple tries. I prefer to have control, TOTAL control of my riding. Just my opinion; an opinion of an old 70yo codger that still enjoys life. I found that if life served me up a high maintenance left hand (clutch hand) then I made lemonade by purchasing a Ryker. Problem solved.