I've been practicing flush setting a lot lately. Like with most things, you get better the more you do it. I recently saw this flush setting vid on youtube. I liked the look of the burnisher he uses so I made one for myself and tried it out on this ring. It is a bit tricky at first, but it gives you cleaner settings and doesnt mar the texture like the other rounded burnisher I'd used before.
This new burnisher was made by breaking an old pair of tweezers and filing and sanding the end to shape it. Then it was glued into a wooden handle.