D at the absolute largest, though I'd prefer a B to C. Sensitivity and mutual enjoyment is more important to me than size. If she can't get off on having them played with, then I certainly won't either.
flat to medium I guess. Probably A to B Cup maybe even C.
Size is not so much as a factor as compared to proportionality with the girl's body type. no point having big tits with a small lanky frame or Plump/chubby with none -_-...