I usually tell people to do sections of the cemetery that look as though no photographs were taken. If a duplicate is created, they can be merged later.
I agree with KV6H. It is hard to tell if any grave has been missed especially since the dots do not line up very well. I have taken pictures in cemeteries that are in very straight rows and the markers face they same direction so I can stand a similar distance from the marker and little tree coverage but the dots on the maps are still all over the place. Sometimes rows off.