Unfortunately, on this incarnation, the disc is a solid mount to the carrier, and the caliper is a solid mount to the fork leg, and one way or another there just isn't enough flex in the system ... it ended up overheating and warping the disc.
I've gone back to a stock R100GSPD rotor, but I might reuse the bracket and carrier from this one for a full-floater setup. A somewhat more professional 320mm conversion is shown here.
Here's some pics anyway. The black rattlecan paint is my fault:
ALL MEASUREMENTS ARE +/- 0.5mm AT BEST!