Hi! I have a 1912 0 size 15 jewel Elgin with a broken fourth wheel. I am thinking about buying a 0 size movement to salvage the fourth wheel from an other parts aswell, but i dont know what movement to buy. Ther are so many grades on the movements and i dont have a clue what grade my movement is. Will a fourth wheel from any 0 size movement fit my watch or are the wheels different depending on what grade the movement is? I have seen some 7 jewel movements with reasonable prices on ebay but havent dared to buy one since i dont know if it would fit my 15 jewel watch..