So I have a few suggested changes to hopefully help with your tuning and the general feel of the aircraft.
First I would suggest a few changes that affect the control system.
This will change the response of the aircraft so I suggest to back off a little on the roll and pitch P gains and add FF gain so you have enough control.
You will have to do the tuning in pitch and roll but with the ATC_RATE_FF_ENAB set to one, the attitude controller will perform better. The ACCEL params limit the max acceleration. I didn't have you change them but the ATC_RATE_x_MAX params limit the max rate. So if after you finish tuning you want a little faster response and rates then you can modify these. Lastly the RC_FEEL param is like a quickening effect. 50 is a better setting to start with. You probably put it to 100 because you didn't have the FF_ENAB set to one.
Why are collective min and mid so close together. I don't know enough about the collective setup in the code but I try to keep mid at the collective for hover like 4-5 deg. What is the significance of your H_COL_MID? Read the swashplate setup for this wiki to setup these params
So lastly, any reason that you turned off the arming checks? I don't recommend this.
So be sure you are comfortable with your swashplate behavior before you fly. The changes I'm suggesting are pretty big changes.