You make a good point about CoM vs CoW. However, while I do think having an idea of Muscle vs Fat distribution would be useful, I would like to point out, Tigers are more muscular than Cheetahs, and Cheetahs run faster. So it is more complicated than either suggestion.
Good catch about Patagium. It is often not connected to digits or wrist. Some connect between limb and torso (with there digits, and sometime wrists, still free), some have it in the middle of an appendage, and certain lizards even bend out there ribs and have it between those.
I actually think @Deus’s idea about Digits being weakened makes more sense.
At least 2 dinosaurs, The scansoriopterygid dinosaurs Yi and Ambopteryx, are thought to have had both Feathers on there body and Bat-Like wings. So I agree.
Um, are you referring to this?