Thanks for the advice.
I probably should have mentioned that I'm mainly only interested in +gram nuggets.
I'm mining upper gravels off a flood plain below a sheer rock walled canyon/waterfall. Gold is mostly 30 mesh or finer with a few pickers so I run 1/2" screens in the plant trying to maximize fine gold recovery. I've yet to catch anything approaching that size screen but one never knows. Like to put a kid on duty checking tailings to make sure.
Above the falls in the canyon and including some old historic workings up above the gold is mainly coarse flake, pickers and nuggets up to 1/4-1/2 oz.
We send friends and family up in the canyon hand planning and they always do really well.
I want to detect the nooks and crannies up on the sides looking for a big score more than anything.