It's a myth that foot size and penis size are directly related...and no, there is nothing you can do to tell if a woman is "tight" or not until you actually visit that area for yourself (even though you're comparing apples and oranges).
If the foot/penis thing were true, it still wouldn't work for women...how tight she is, is more related to how much and what size "action" she's had. That's not the same thing as penis size, which doesn't tend to change over time.