The rib has significantly less science in it than everyone is thinking and more qualitative estimate. I tend to like the sound of the long scale basses with smaller bodies than the larger bodies. After much trying of various basses and tapping on the bodies I decided that some of the tonal difference was coming from the more hollow sound versus the more solid sound of the smaller bodies. So I added the rib to get the chamber sizes down closer to the smaller body chamber sizes and limit the maximum span of the top and bottom. I also know that this may have had little to do with the differences i was hearing since most of the tonality is in the neck. And I added ebony to this neck, which none of the basses i tried had. Additionally, this bass body is a modified version of the previously featured Hot Lava body and Mica noted that it sounded great, but was a little boomy, so if the body chamber sizes were causing that, the ebony would likely make it worse by strengthening the lower resonance points.
Soooo....I''m holding my breath and hoping the rib will move the tonality in the direction I want.