Hi Tom
Due to distractions, I have only just picked up my TC2100/0.9 degree motor project again (previous posts were under Beta Firmware Releases). I now have the Watterott TC2100 drivers working under 8.11 and they operate extremely well - very smooth and absolutely silent.
For reference, with the Watterott boards, the CF1 and CFG2 pins need to be open circuit to operate in 1/16 step mode, other than that, no jumpers/soldering required.
Strangely, I am unable to get 8.11 running on my DRV8825 based controller - am investigating that currently.
Regards
Dave