In the park when I want to limit hole size I noticed in the wet that I run a little less sensitivity than the dry, (3 vs 4-5 on ace 350) and the pinpointing accuracy of targets deeper than 2" is pretty good compared to dry. Dry accuracy has always been a little off. The beach is odd though, since I use a scoop instead of a spade or screw driver, it's hard to say since the scoop size is within the margin of error. I have found big stuff like soda cans, rebar or bolts and cut off sign posts 12"+ deep. I don't go past the high tide line though because it becomes unsearchable.
Target ID for ring pulls was really good, but most other stuff was sort of accurate to inaccurate. Steel bottle caps are coins, aluminium bottle caps are coins or pull tabs, modern soda can tabs are coins, brass shells are coins, coins are other coins, foil, nails and wire are everywhere, iron relics are usually iron.