I use one of these throttle rocker, I like the one with the velcro strap to clamp it on but they are available as cheap as $5 and as expensive as $25. You rest your palm on it to keep the throttle open instead of gripping the grip. throttle rocker

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!