Well I bought a cowl that's 12 1/4" it looks about right on the plan I blew up. Now just have to make the blisters for the cowl. I see the blisters kinda are paired on the Pica plan. Its the ymf-3 correct? and evenly spaced would be on the YMF-5, right? I'm currently building the 72" Pica plan and I getting ready to build the bigger one and I just wanted to be right.