Ask away, plenty of information locked away in this head...
What film did you end up with, 3um? Did you heat treat it at all? That might help... I do have some ovens to play with. I was also toying with the idea at work today to design a PCB driver and have it made at a fab house. Those guys can do amazing tolerances and different materials. I did do this once but the design was flawed. Now it would be just one design for the stators and another one for the spacers.
About the squeal, first attempt will be cleaning the diaphragm as they are dusty. The copper oxidizing is an issue but I'll probably first try some polish liquid which forms a protective barrier that stops oxidation. I used it on my KGSS back in the day and the bare aluminum is still nice and shiny.
Edit, some pics:
Edited by spritzer - 4/20/13 at 4:51am