Reverse Y6 VTOL

I’m in the process to build Y6 tilt rotor. My Q_FRAME_CLASS=5 and Q_FRAME_TYPE=10. It’s Y6B configuration but motors 3 and 4 are in forward position. To build reversed frame type it was suggested in “Reverse Tricopter-VTOL Plane” topic to try negative pitch PID gains. So Q_A_RAT_PIT_x are set to negative values now and it looks like a workable solution for my configuration. The issue that I’ve got so far with such approach is arming. I have to switch it off, so ARMING_CHECK=0. This combination (pitch negative PID gains and disabled arming checks) works but makes me feel uncomfortable. I tried to switch off only dedicated checks, e.g. PARAMETERS but without success. Any value for ARMING_CHECK that is not equal to 0 leads to arming failure PreArm: Bad parameter: ATC_RAT_PIT_P must be > 0 . I’m using Cube Black with Arduplane V4.0.5.
Would you suggest anything to keep arming checks enabled?
Are there any known issues associated with using negative PID gains?

Thank you