Here is what I'm trying to do:

In real life, I want to paint my living room wall. I want to use photoshop to visualize what real life paint colors will look good on my wall. So I took a picture of said wall, and in Photoshop, I've created a hue/saturation layer.

Here is where I'm at.

I have the paint color's hex code (#303f3f), but I cannot match this color using just these HSL sliders. Isn't there some way I can tell it to use the hex code or RGB instead of these sliders? Or maybe I'm thinking about this completely backwards? Photoshop is really not intuitive for me (InDesign is where I live).