@sr71luis yes we use one back from the latest arducoper firmware. Of course recently they changed how it looks in Mission planner to upload new firmware. Now you get a bunch choices… no write up as to what it does or why it is like this… drives me nuts.
I would have to check compass_typemask but I have left it as the default.
FS_EKF_TRESH I have not adjusted. It seems happy enough on all EKF issues if you can ignore the in flight adjustment 
AHRS_YAW_P I have not messed with either.
For me when I face the drone North as per any compass or a map then power on the drone the compass faces up to 45 degrees NE… as soon as you take off the compass adjusts to the correct north. Different GPS’s give different angles on the ground which drives me completely insane.