How to select a spot colour from a graded fill to colour a stroke?

I've created a graded fill using points. Now I want to select the colour from one random spot within that shape and use it to colour another stroke (that doesn't have a fill). I've tried double clicking on the eyedropper tool, picking up just the focal fill: color, and applying focal stroke: color. That just picks up the whole graded fill and fills the stroke with it.

At a push I'd be happy if I could just sample the colour at a spot in the graded fill, and get a readout of the colour, and then type that into my stroke. I can't work out how to do that either.

What I'm doing is drawing birds. The graded fill is great for background colour, but then I want to draw feathery bits using strokes, and I need to match the strokes to some parts of the graded background fills. Right now I'm doing it by eye, and there has to be a better way.