I have been band-aiding the same issue for a while. There are proportional gain settings for the O2 at idle which can calm the idle surge down. Lower the proportional gain settings under O2 PID Idle Parameters in Parameter category view. I also lowered the number of counts in Proportional Counts vs. Slow O2 error to smooth the surging at cruise. This table is under Fuel Trim Parameters. There is also a table in there called Proportional Flow Gain Factor vs MAP vs RPM which has some effect on the O2 switching. I finally repaired my ostrich emu and hopefully the weather will break soon and I can do some more testing. I haven't been able to find a normal proportional gain setting in $0D for the O2 sensor. When you make changes, look at the O2 swings using Show Data Monitors to see the results of your changes. The surges are caused by the O2 gains and overshoot. You can see the surge in monitors while viewing live data. I usually turn on O2, BLM, INT and Calculated airflow since I added it to my adx file and modified my bin to show it. Some of the others may be able to chime in and have a better method. I have been trying to figure it out on my own. I run a Howards cam 180245-10 so my calibration is quite different from stock. I'll look at your datalog this evening.

Hope this helps,
Brian