How high to set your bait varies due to a number of factors, such as time of day, bait species, water clarity and how aggressive the fish are on that given day.
For instance our typical setup in CT where walter feeds on perch, crawfish and shiners/alewives is in 15-20 feet of water during the day and 2-5 feet after dark. Baits are 1-3 feet above bottom, closer to bottom in the shallow water. Most lakes are slightly stained, the clearer the water the farther off the bottom we set the bait. A word of caution-make sure the bait stays at the desired depth, you may need a little weight, just not too much as they are very sensitive to resistance.
A famous walleye lake in NY is normally very clear and we have had aggresive walleyes come 6 feet off the bottom during the day. This lake is known primarily for the jigging action during the day and has a reputation for no action at night, which belief I can say we have thoroughly debunked.
At night the fish cruise the shallow water same as other lakes and can be caught on tip-ups with the bait a foot or so off the bottom.
Our best success with walter is with relatively light leaders, even at night, 8 lb fluoro and a single split shot. In shallow water at night stealth is critical, pre-drill your holes before dark and set up camp at least 100' from the nearest tip-up. Use tip-up lights if possible and avoid shining your headlamp around as they will spook from the light. Don't use creepers or run if you can avoid it, if a school is hanging around in your spread when you tend the first flag they will split quick.
