I think I am going to try this throttle on the Avenger. It has a twist throttle and a thumb throttle. If your thumb gets tired you can use the twist throttle or if your wrist gets tired you can use the thumb throttle.

The twist throttle is lockable so that when you are using the thumb throttle, it stays in place and won't rotate. I haven't even opened it up yet to see if I can make a throttle cable work with it but I thought I would give it a shot.