My understanding is that the distance from the pivot to the firing pin (hole) is adjusted in the Colt's factory by selecting a hammer of the correct height. You can't move the hole in the recoil shield and you can't move the holes that hold the hammer pivot pin in the frame. That means, I'm sorry to say, you'll have to find hammers with the correct dimensions. The hole in the hammer, behind the firing pin, is used in the factory for inserting a rod through the hammer and recoil shield to determine if the hammer at hand is the correct height. That is the first step in picking parts for assembly. Sorry.