Understanding REX Assist gains.

I am setting up my first REX Assist receiver. So far I think I have it OK but I want to make sure I understand the setting and function of the gains.

The aircraft is a scale warbird P47 1.8m wingspan

I selected an airplane Aerobatic Precise. I think this is the best one for a scale aircraft?

In the airplane settings you can set the gain for roll, pitch and yaw. These remain as the default values for the aircraft type mentioned above. The settings are Roll 18, Pitch 20, Yaw 25 for damping mode (I have some lower setting for heading mode). My understanding of these settings is they are global settings for each axis?

In the Flight Mode Settings you can also adjust the gain for modes M1 (Manual assist off) M2 (Normal Damping) M3 (heading hold). At this moment I have set the default gain to 0% for M1 as I want this to be purely my control of the aircraft.

In Flight Mode M2 and M3 I have set the default gain to 20%. Does this apply 20% of the gain set in airplane settings for roll pitch and yaw? For example in airplane settings the pitch is at 20, therefore in M2 I get 20% of 20 = a gain of 4?

If this is not correct please can someone provide the correct answer.

Finally a question about adjusting the gain in flight with a proportional channel. Once I have adjusted the gain in flight how do I find out how much the gain has been adjusted so that I can then change the Airplane Settings value and the M2 and M3 default gain%?

thanks.