float tube seat height

[sumo]

Ok i am new to this type of fishing I am currently building a version of a float tube/pontoon boat and I have come to the point of determining how high i want to sit out of the water, I have never used a float tube before and would like some advice on how high to mount the seat , I know that the over all height will vary from person to person. I have noticed , by looking at the pics on this site that some tubes sit you below the water line some just at the water line and some out of the water all together, is their any advantages / divantages in each position or is this a personal preference . I have included a drawing to better show what i am working on.
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