Jeff,

New or older dredge ?

Enough throttle for good suction, box water flow
That may require full throttle depending on HP and conditons
Enough slope on the box to move rocks off but not enough to scour out the riffles
Try and keep the tail of the box outa the water via flotation
But you want to keep the box low to the water level to help with suction by not having to lift the material any higher than needed
Its a balancing act, good suction, good water flow but not to much
Dont raise the nozzle out of the water, go slow on the nozzle to avoid plug ups
If your not under water bring ear plugs

Most of all, enjoy your time out there,
Bill

I run my high banker at about 10degrees. Steeper to get more flow and shallower for slowing water if your sluice loads to one side. Lower that side very little until the box is even

Well, I've never been to Georgia, let alone mined it, but Doc from Gold Hog insists it's more scarce but larger pieces... you might get away with steeper angles, but overall, your angle will be determined by the activity in your box while running it. this is determined by the type of material, as some minerals weigh more than others (Tungsten being almost equivalent to gold and, in my area, more prevalent). if you can, have 1 person operate it while the other monitors the sluice to adjust accordingly. you want the box to clear the majority of what was put in it while leaving the heaviest of the feed behind but still fluidly moving.
The key to good Suction is to keep the Jet as close to the water as possible. Even 3 inches above the water reduces your suction quite a bit.
Also, control your feed. it is entirely too easy to treat it like a shop vac first thing and bury the nozzle in a huge pile of sand, which will quickly clog your line as fast as an oversized rock.