Hello,
In Google team papers they an updated version of CTC configurations as follow (which I use in my papers too):
./aomenc --verbose --psnr --frame-parallel=0 --tile-columns=0 --passes=2 --cpu-used=0 --threads=1 --kf-min-dist=1000 --kf-max-dist=1000 --lag-in-frames=19
--end-usage=q --cq-level={24, 28, 32, 36, 39, 43, 47, 51, 55} -o {VIDEO_OUTPUT_NAME}.webm {VIDEO_INPUT_NAME}.y4m