Like mentioned above, if you set your float just like regular drift gear, your bait could hit a number of different current drafts that will either take the bait to or away from the fish. To get a consistent depth you can count on, do like Bob said and run shot at different intervals OR get some small barrel sinkers and paint them your favorite colors thus creating a "lead corkie."

The only thing i hate about pinching shot on your leader is that it can create friction if you get a hot fish on, or the shot can rub or fray weak spots on your line.

Another option is curing your eggs with a "hard cure" making them tough enough to put strait on your jig hooks like you do shrimp.
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"I have a fair idea of what to expect from the river, and usually, because I fish it that way, the river gives me approximately what I expect of it. But sooner or later something always comes up to change the set of my ways..."
- Roderick Haig-Brown