Sounds to me like you are well on your way to being a very good detector user and your finds should be very good too if your locations are target rich.
I think some of the ghost signals is metal that totally disintegrated so the iron leached into the soil. Also think some of the frustrating tones are iron buried deep.
If it's rocky terrain I would think most coins would be in the top few inches. The rock composition might have a lot of iron causing false signals with the equinox and the pinpointer.