All great ideas. I'm all for keeping the slider as well, also remembering where you left it or maybe the current color. That way, if you're managing a couple tubs it will be the color of the one you target. Having the number displayed instead of able to be entered would be an acceptable compromise.
There was a formula for figuring out the hue based on the row, column, and position of the brightness slider. Trying to see if I can find it somewhere...
I also support this. However implemented, but being able to target exact hues some how would be really useful! Weather it be an numerical entering option (Keep slider, for those who wish to dye visually and not numerically), or just showing the number, or remembering last color to aid in fine tuning. Bottom line: Yes please!!!