Colorize - how to sample color within preview image for color points in the colorize window?

When in the Neural Filter for colorizing there is the filter window (with the sliders and the B&W  image at the top) where you can change colors of objects and refine how the filter is applying color. As you do this you can see the changes on your full size preview image in the main window. I want to be able to sample a color from that main window to use as a point to be applied to the B&W image within the colorization window. Sorry, I don't know if I'm explaining this very well.

If I click on the "color" box below the B&W image in the colorize window, it brings up the color picker but now I want to be able to pick that color with the eyedropper tool from my main image window. For instance - I like the color the filter has choosen for someones shirt but an arm of the shirt isn't colorized properly. How do I first sample the color I like before adding that color to the B&W image in the colorize window?

While I'm here...is there a way to make the B&W image in the colorize window larger so it is easier to apply color points?