My significant other thinks I should do it that dark too. I'm torn on it. I like the darker edge too but just want the binding I worked so hard on to show nicely.
Oh did I mention that on that sample that if I turn it 180 degrees the dark flame almost completely disappears? I have high hopes for this finish.
Here's the deal. Your walnut is medium brown, almost dead center on the scale of light to dark. The best way to get it to show is by using high contrast. Your choices to do that are either to go light, the extreme of which would be to leave the top natural, or to go very dark, which you have already tested. To my eye the dark is more visually exciting, plus you get that cool flip. This not unlike John's choice with his hands of God inlay. He was torn between a maple fretboard or a dark one feeling like the maple would show off the wood of his scroll work better. He was afraid the contrast would be too low and the darker woods would get lost against a dark background. But he went with the wenge board and of course it looks great. By the same token, your walnut binding will be quite visible against that dark tobacco burst you've created.
SR