You don't want to be sitting on a rib, that's why it's moved forward. It's less important depending on what you plan for a seat. I don't think it's as critical that you sit all of the way down on the skin like in a traditional SOF, but you still want to avoid sitting on a rib if you can. I've paddled a Schulz-built F1, but to be honest I don't remember what the seat was, or if there was one.

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