While it's nice to have compact controls, I feel that in this case the lack of any range or value indication hurts usability. Have you considered adding support for labeled tickmarks to your vertical sliders? Displaying the current value directly will probably bring its own UX issues, unless the output element has a fixed width.

good point, as you can see I usually end up printing the value of the output out as well to get the numbers in a copy and paste form. I think probably the value could go above the slider if formatted appropriately.