Perhaps you are more interested in being argumentative then seeing the point. My last post is an explaination that thin airfoils can be quite stable a slow speeds. I did not claim that the bled off energy quickly.

Airfoils: depends on how specific you would like to get however IMO there it 90% of the time is a wasted effort unless designing a sailplane or a pylon racer. That is when staying within the same family of airfoils. Clark Y, Semi Symmetrical and Symmertical are generally the three choices. Choose which one to go with based on aircraft requirements, choose the thickness and then set the high point at 30%, draw a smooth transition from leading edge to trailing edge. Works every time.