as to depth it'll depend how deep the water is. plumb the depth first with your float set up until you find the point where the float just 'cocks' and then alter depths as you like, depending on tide height and if you're catching fish. usual baits rag, maddies mackie strip will suffice.
if your're targetting bass, clear bubble floats may work better for you.
All according to what species you are targetting. Macks and Gars, you need to be fishing reasonably high in the water, Wrasse, tight to the bottom, Pollack from bottom upwards. Keep adjusting the height to find the depth at which the fish are feeding.