I just got my GT a week back so I can't be much help. I do live on a CW campground and have found several bullets and buttons so far with the GT. The first thing that helped me was figuring out "the wiggle". As a kid we would make a pencil look like it was made of rubber by jiggling it back and forth with a loose wrist, its kind of like that. When you hit a signal you wiggle the detector side to side an inch or two, back and forth, and if the tone locks on it's usually worth digging. I read to use auto sensitivity if you're new, but clicking right out and leaving the knob full counter clockwise seems to give several extra inches on depth.
I had a solid signal the other day and dug a hole and the signal disappeared. I knew the signal was too good so I got my MXT, with a smaller coil down in the hole and the signal was strong. It turned out to be an infantry button...this was before I switched out of auto sensitivity. You probably already have a pinpointer, but if not that will definitely help.
I've still got A LOT to learn myself, I hope someone with more experience with the GT and CW sites will jump in...I need advice as much as you.