Bait Presentation when float fishing

This might sound an obvious question.

When float fishing for mullet etc, how should one present the bait, ie at what depth? Unless you are fishing on the bottom, surely a bait will just bob around with the waves and look unnatural?

I am a coarse angler who takes a rod to holiday destinations and have found this a problem in deep water, ie off breakwaters etc.

for mullet i free line bread off a pier, rock etc, or if i need to cast do it the same way you would for carp with a bubble float.

as for other baits keep changing the depth till you find the fish. worm, crabs, shrimps, sand eels, even the shrimp type feathers all work on a float once you find the fish.

if you watch small crabs etc they just float around in the water and so do almost all the other baits. the bobing up and down dosnt bother the fish at all as they are used to the movment.