For those of you flying with the kk2 boards you must change the motor layout in the mixer settings. But first make sure your control board is always centered over the center of gravity, indicated most of the time by the rear center hole on the plates. Because the motors are not at 45 degrees to the frame you must tell the board where they are.
My settings are:
These are the correct values for the mixer editor but regular tuning is then also needed. You might have to tweak the mixer editor settings if you modify the original design or change the center of gravity. Or you might have to adjust the throttle and rudder settings to suit your needs. To modify the settings or just verify my findings, this video https://www.youtube.com/watch?v=--xTRlx7GK8 explains how to measure the angle of each motor and also how the kk2 settings work. The link to the spreadsheet in the video will also help you with any other asymmetrical multirotor builds.
I hope this helps anyone with a crappy flying quadcopter!