In my opinion. Default setting should be for advanced and the 90 atti, .30 .30 expo. Should be for those of us just trying to learn. That's why we askFirst thing is to read warning on bottom of Gain Settings page: "Only advanced users should modify these settings. Any changes will affect aircraft attitude and gain. Make adjustments with extreme caution."
Expo just changes the linear effect of stick deflection to a curve, meaning the deflection from neutral is either de-sensitized or heightened. I like being able to do smooth yaw with the aircraft, having owned the P1 and P2, where the gimbal had to follow the aircraft and to get a smooth pan meant being very careful with yaw stick deflection.