I've done a few 500-550 mile days and I just open up my fingers and apply pressure to the throttle with just the palm of my hand on long interstate stretches. Gives me a chance to wiggle my fingers and thumb to get the stiffness out of them.
I've ridden a Bonneville with a throttle rocker on it. Just felt too wierd for me. I can see why people put them on, along with things like the Vista cruise control. Don't have anything against them, it's just not for me. And who knows, maybe when I hit 60 I'll be making those kinds of allowances. Heck, with my bad knees I'm just lucky to be riding at all.
