If you add a white line in both the inner and outer toe coils like in the picture, pinpointing becomes so easy. All you have to do is find a target, run the target dead center over the inner coil, (bring the coil towards you) and when the sound suddenly stops, the target is between the inner and outer toe coils. I tried it on 160 coins that I dug today, and it was soooo easy.
To find the center of the coil, trace out the coil on a piece of paper, cut out the coil, fold it in half and you now have a crease running through the exact center of the coil. Return the paper-paper drawn coil under the coil, and with a pencil, mark the center points on the inner and outer toe coils. Get some white tape or sticky back paper, cut a small strip and paste it on the coil. Cover it up with a coat of nail polish, let it dry and you are finished. Now get out and practice practice practice, and you will be popping those shallow coins very quickly. Good luck!
To find the center of the coil, trace out the coil on a piece of paper, cut out the coil, fold it in half and you now have a crease running through the exact center of the coil. Return the paper-paper drawn coil under the coil, and with a pencil, mark the center points on the inner and outer toe coils. Get some white tape or sticky back paper, cut a small strip and paste it on the coil. Cover it up with a coat of nail polish, let it dry and you are finished. Now get out and practice practice practice, and you will be popping those shallow coins very quickly. Good luck!