Yeah, I saw that done once before. If my memory recalls, I tape the cardboard to the fuse then mark and cut out the places that the items, muffler, needle valve, ls mixture adjustment, and so on, then slip on the cowel without removing the cardboard templates, transfer the cutout positions to the cowel then cut them out. Sounds simple enough.. but believe me, I can make any simple project turn into a major headache..ha.. oops... sorry about that.

One more quickie. I have seen some pilots set up the fuel lines so that they pass from the tank to outside the cowel on the side, through a metal tube (brass) then back into the cowel to the engine. This seems to facilitate refuel and a place to pinch the fuel line to check hs mixture. Ever done that one?

DS.