one thing you may want to check before making changes to the hammer/nipple, make sure you have room for the end of the mainspring to extend further down. If you let this hammer rotate further forward/down, it will let the mainspring droop a bit more.
you can check it now, with this hammer/nipple combination. Then try to determine if the mainspring will interfere with wood in the lock inlet if this hammer goes further. it might not move much, but sometimes there is not a lot of extra room in the lock inlet.
What you find may dictate if you can use current parts with some modifications, or if you'll need a new hammer cut to fit this tumbler/lock. its easy for one small change to lead to another issue.