Riding a similar configuration here. Radix, 2011 Magura including clamps.
Had Heatsink Blue with Kabra/Bonz rims. They were really good in the dry.
Tried to switch to TNN ADM for the last winter for wet rides:
Just threw them on, and my brake performance was gone, no honk, no bite, no hold on the rear,
some hold on the front. Switched back to Heatsink Blue, front was ok again, rear shit.
Tried adjusting, tried grinding, different grinding discs, new rim, let others grind, nothing. Not
with the original Heatsink Blues, not with the new ADMs.
Bought a Because rim for the rear, which has parallel sidewalls.
Also TNN clamps. Grinded with a very thin, new disk, barely touched the rim
to give it the smoothest of grinds. Now the brake works with Heatsink
Blue again, loudest ever, good bite, fair hold, even in the wet (!), for almost
three weeks or 25 hours now (without sand or mud).
I still have the TNN ADMs, and I will try them on the new rim with the
TNN clamps, report back here.
I came to the conclusion that I am just too stupid to properly
align pads and rim with angled sidewalls and Magura clamps.