Wow Michael, you sure put a lot of work into that!! I don’t know if I would’ve done so….
I had the same harp. My levers weren’t as stiff as yours, but I’ve heard about that. Mine were just… very bad. The tiny metal bar that pinched the string, was crooked. In all of the octaves, every F# sounded different. LOL! I just didn’t want to replace all of the levers.
However, the sounded grew a nice little pot belly on it, and the sound matured after a year. It sounded quite good.
PS: I had sold that harp, and the woman who bought it uses it to play with a group at church! They started a lovely little group and she’s having a blast! The neck did crack on the instrument, but she found a book to fix it, and apparently she did fix it!
Goodluck with your levers and happy harping!