SS5:
2 big toes approx 300 crystals.
4 small toes approx 200 crystals per foot.
So full set of toes approx 300 + 200 + 200 = 700.
Nails I would expect to be roughly the same maybe another 100 crystals, although you would use less on the thumbs than on the big toes you would use more on the 4 fingers as most fingernails are bigger than the little toenails.
You should defo get 2 full sets from a factory pack BUT there are the obvious variables to take into account, nail length, width and crystal size and how close you pack the crystals onto the nails.