RE: modifying CG Super Chipmunk
I'm building a Goldberg chipmunk right now.
it will work you can make it also oval the only thing is you are adding weight that will also influence the CG point.
an ounce here another ounce there and suddenly you have additional 2 pounds that you will put on these looking for mercy LG...
no body is looking how under the wing looks like, put a pilot figure its the canopy that attracts attention.