I've got some screws (top lever, top tang, trigger plate, etc) that are what I would call "over-timed". Put another way, if they are as tight they should be, the slots will be past the direction that they should be pointing. Complicating this further, some of them have heads that are fit to the curve of what they are positioned in. What are the strategies to fix such problems?

The issues are with the Alfred Field, and I cannot make new screws nor buy replacements from Mr. Field.

Thanks!