I FIRST made one of these set up jigs for the pinecones, It worked so well that I made one for a concert build last year. I have just completed this one for tenors. The "turtle" holds the sides in place as you assemble and attach the sides to the top. It has been a great improvement in my process.
you can see how it holds the side in place as you attach them to the "butt plate" Oop's, I need to make the butt blocks and glue them on.
And finally, the four pinecones are almost done. Maybe one more application of the thinner French Polish to really make them sparkle. Then I will be attaching the bridge and the Pegheds. These beauties will be singing in another week.