+Matt S - To adjust your tube height, remove some of the rubber spacer, do not tighten it down trying to compress the rubber.
Do I remove the clamp and shave down some of the rubber?
Loosen the clamp off. The rubber under the tube is usually 2 or 3 layers, try removing a layer and then retighten the clamp. You may need to remove all the rubber and then insert a cushioning material that is thinner than the rubber was. Hope this makes sense to you