Im building a four star 60 right now too
. Ive only finished the wing, but i already have a plan to build the cowl, which wasnt part of the original design, kensmithjr. I plan to mount the engine with the spinner, putting 1/8 pieces of wood behind the spinner as spacers. Then ill put a balsa ring slightly bigger than th spinner on the back of it, and use triangle stock balsa to connect the ring to the body. After that you just sheet around the triangles and sand the triangles down in the corners to get the nose to flow with the spinner.
I have a question about sheeting the turtle deck though... The stock turtledeck pieces are flush with the side of the plane, so when you sheed the turtle deck it will add some with that will protrude off the side of the plane. How did you get it so the side of the turtle deck was flush?