Today's first task was to finally tackle the lower cowling exit. The goal is to match the exit hole for the oil cooler plenum with a 1/8" gap all the way around. I found I could easily get the 1/8" gap using thick cardboard sheets and wrapping it in duct tape. Deciding on the final oil cooler plenum position was critical so care was taken during the installation, the same as the new air filter box install. Using only 1 ply UNI all around I set the gap from cowling to cooler. Later this ply will be re-enforced, but using 1 ply at this stage will make for a much easier removal after cure.