I pop coins using the Revis method if they are less than 2 inches deep.
The best method for digging coins if you can't do that or if your target is deeper than a few inches is to use a sharp digging tool to cut a small C in the sod. Fold back the flap and use your Pro-Pointer to see where the coin is, either in the flap or still in the hole. If you have to remove more dirt from the hole squeeze it into a ball to keep it together or place it on a small square of cardboard. This will allow you to return all the dirt back to the hole. Replace the dirt, fold back the flap, and press it down. As long as there is some moisture in the ground the grass will not die and the flap won't get kicked out of the hole like a plug sometimes does by a passing mower. Also shallow plugs tend to turn brown where using this method the grass will stay nice and lush. I rarely take more than about 10 seconds to find coins down to about six inches and it's virtually impossible to tell I've been detecting when I leave. As you noted, accurate pinpointing is a must for whichever method you use. The Pro-Pointer is well worth the cost.
Chris