I've been on a huge tweaking kick...I play a lot of overblows and set my harps up as such. Here is a list of what I do and in what order.
- tip scoop
- Ruper Oysler's, "radical reed shaping"
- opening up the backs (not on Golden Melodies, though)
- attaching labels
I tune to 443. I don't really play hard, but the harps have more cut this way. I can also use a deep blues vibrato and not get pitchy. Most of what I learned has been from Chris Michalek and the Ruper Oysler video.
I have the Herring tool kit along with a lot of other tools I pick up here or there. The most recent has been diamond tipped bits for a Dremel. I use them to scoop and tune.