I have a throttle rocker, or something similar. I find I just have to remember to relax a little bit, and also when I am going down straight stretches of road I just rest the heels of my palms on the grips, and flex my fingers for awhile. If I do this every 15 minutes or so my hands don't go numb. If they do I just flex for a few minutes and it goes away.
2004 Vulcan Classic 1500 - carbed
Grips, Freeway pegs, engine guard
Floorboards, Nomad rear seat,
Custom made luggage rack, Windshield & Lowers
Saddlebags, Passenger floorboards,