Well, I had to mess around a fair amount and double back more than a few times, but I finally figured out how to fill the design on a Whalen reallllllllllllly nicely and very easily.
I'll be selling the technique on eBay starting at $15.
Final technique is soooooooooooooooo simple!!!!!
I used Rustoleum Oil Based Protective Enamel.
8oz tin was something around $5 (?) I think. Anyway, not much. And I still have enough left over for another hundred knobs.
I took a paper towel, dipped it in the paint and just kind of blotted it into the grooves. The effect that worked the best was getting it so that there was a thin film over the whole design area, and the design itself showed through darker than the rest. IOW not so heavy that you can't see it anymore, but heavy enough that the grooves are filled evenly.
Next part was the
bit. I tried I don't know how many ways to get the excess paint off without pulling paint out of the design. The best way by far: wait just a few minutes, and take a small pad of paper, like a postit note pad, and holding it fairly flat, just rub over the painted areas. When it gets too much paint on the page just tear it off and start on the next. It took a little bit to get all the extra off, but you can rub as hard as you want because the paper isn't going to absorb below the surface of the ball.
I left it over night and did it one more time, but really there was hardly any improvement.
And here's what it looks like