I do have that setup. I'll tell you one thing, the thumb throttle is the best i've ever used. Huge and extremely comfortable. I can always find it no matter what position my arms/hands are in
There are rubber "cushions" inserted in the ends and that supposedly dampens vibrations and shocks. I'd say it definitely helps as opposed to gluing grips straight to the bars.
It's pretty much like having a twist throttle sleeve on both sides. But they obviously don't rotate at all like a twist throttle.
If you give me till tomorrow, when I take out my motor, i'll take some pictures of the setup so it can help you make your decision.