After doing Section 6 (Vertical Fin) I now knew why Hardik had been puzzled by the fit of the Ribs in Section 12 (Stabilizers). Section 6 step 5.1 talks about angling the plastic Rib Inserts and the aluminum Ribs. So I grabbed the Stabilizer frame that Hardik had assembled previously, drilled out the Rib Insert Rivets, angled the plastic Rib Inserts with a Dremel, angled the Ribs with a hacksaw and put everything back together... looked great. When Hardik joined me later in the day he was good enough not to ask me why I was having him do the sections out of sequence and therefore not getting full knowledge out of the instruction manual. He banged together the second stabilizer frame in quick order including angling the Rib Inserts and the Ribs as needed.