Tail Yaw Drifting Help

Thanks for any help in advanced, I am still in the learning stage but trying.
APM 2.6, firmware ver 3.2.1, Trex 450 clone, Tarot FBL head, Emax digital servos, Flysky TH-9X.
I have received good advice from people on this forum, so I will ask again. I have been trying to adjust parameters to improve hover ( lot of drifting) I cannot raise roll or pitch P values much more because I will get osculation so I have found some improvement raising I values, changes are made in full parameter list.
I may have made some changes in parameters I should not have changed, but now I have no idea what to try to correct?
Problem is now the tail yaw is random drifting right and left and will not hold in one direction as it used to?
I have attached a parameter list and any Help is appreciated
450 Heli Par File 8 10 17.param (5.4 KB)

Hi William,
This is the rate yaw settings you have
RATE_YAW_D,0
RATE_YAW_FF,0.025
RATE_YAW_I,0.04
RATE_YAW_IMAX,1000
RATE_YAW_P,0.2

I think the yaw I gain is pretty low at only .04. I would suggest .25’ish for that and see if it helps lock that tail in.