Maybe I misread something; if so, please accept my apology. I wasn't arguing for dihedral affecting longitudinal stability in any important way. I did write a post that touched lightly on the vertical difference between AC and CG and thrust vector.

Based on your last post, I don't think we actually disagree about anything important.

I am not an engineer, but I am an ATP ME, CFI/II/MEI with several thousand hours professional flight time (and aerobatic competition), former air traffic controller and current FAA terminal instrument procedures specialist, 30 year modeler, and have studied a bit of theory in my off time. Don't want to give anyone a false impression about myself. If I tried, someone like you would certainly catch it quickly.

I don't disagree with your statement but you can bet that I will continue studying anyway, for my own benefit.