I’m not sure of your point, but I will comment to your post. In your comparisons, it appears that one thing you have not gleaned from your Kitfox history review is the size of the fuselage in the 5 to 7 is relatively the same. The model 4-1200 fuselage is much smaller, resulting in the lower weight, resulting in the performance with the same engine.

just some more to chew on.

Ralph