On the topic of RDA, I was just fact checking for the above post and noted that:
1. RDA say that even 15 microns of disc thickness variation (0.0015 mm) can cause brake shudder,
http://rdabrakes.com.au/page/TB06.aspx (halfway down page...)
2. Maximum acceptable runout is 0.15 mm
http://rdabrakes.com.au/page/TB01.aspx (again halfway down)
Its not hard to imagine that if a disc has 0.15 mm of runout then the pads will have no trouble at all chopping back the high points to produce well in excess of 0.0015 mm of disc thickness variation......
I've emailed RDA to see what they think about all this