RE: CC Edge 540
I'm not sure about weight saving but there is a 10 mm coroplast available that weighs about 200g per sq. ft. It would only need hardwood engine mounts instead of doublers and bracing spars. The 4mm is about 70g / sq. ft. times 2 + doublers etc. A cheek cowl was always a must for the goodyear racer profile planes. It made a much better motor run and a stronger joint on the profiles. I like that design. Looks good, gives me ideas.