I can't help but think that women with thicker thighs are much more likely to have tighter vaginas than those with skinny. Seeing the huge gap some women aim for makes me think that since its never close together as much, it won't really be as tight as a women who had thicker more fuller thighs
it really doesn't depend on the thickness of a girl's thighs. that won't affect the tightness of her vaginal canal. maybe her labia will be tightly pressed together but it all boils down to what's on the inside. in my opinion, having your thighs too close isn't the best thing for a girls vag, it does have to breathe after all!
Your choice of pictures in interesting because it's well know through self admission that Rihanna is bigger vaginally. I suppose tightness could be perceived based on the differential between the size of the man and the size of the woman?