Almost done, not quite 1.0 yet but close enough to release.
Range: -10 to 10, but the negative end doesn't really do much. The positive side is where it actually works, you can push it pretty far if that's what you're going for.
Pretty straightforward. Does what it says, sometimes creates weird side effects that I've noticed. Just a functional tool for when you need that specific kind of proportion control.
Also, comment below what types of sliders you might want. I'm creating a training list.