I use lane 1 w/AP1, and lane 2 or 3 w/AP2 depending on traffic conditions.
Not comfortable with AP2 unpredictably hunting/overcorrecting while in the HOV lanes.
Only reaction to MCs occurs once detected by the front of camera, which may temporarily slow TACC depending on MC speed and always displays the MC on the dash. The side sensors do not move the car, only display location sensitivity similar to any other obstacle. Hopefully, the side cameras will eventually trigger defensive actions but I don't experience anything now. Do others?