So it's my first time using a 32-bit Basecam, and my first time setting up a 3-axis gimbal. I've previously only used 8-bit + 2-axis gimbals. I've managed to tune it and it all seems to be working mostly correctly. I have RC pitch control only, in angle mode, and that works fine. However, when I start it up it seems to pick that as the home position.

In other words, if I make sure the gimbal is level and power it up, then it will hold that position. The RC start angles are all set to 0, and I can physically see that the indicators on the GUI are showing the black arrows in the correct position, so the camera IMU is configured correctly. The frame IMU is also configured correctly. Gyro is set to use saved values and not try set itself up on start.

Just to provide some background: my aim with this is very simple - I have a custom payload on an RCTimer Black ASP gimbal. I want it Basecam to basically lock the yaw position to whatever the aircraft's heading is. I want Basecam to keep the roll perfectly level (ie. as the IMU was tuned). I want the pitch to match my PWM output where 0 is perfectly level, -1500 is 90 degrees down (-90?), and +1500 is 90 degrees up.