I know those planes - - the canopy thing can be tested with some tped on bits of thin hard foam /balsa cardboard etc. this is one of those things that happen when "everything is just right" you can't calculate it - it is just a watch and see thing-- and quite a project - I have some local friends who do vintage scale stuff - Orville Lloyd and Noal Hess- Noal has a room full of trophies from many years of scale stuff. Orville did the Liberty Sport - full scale and loves vintage scale military