4 Channel Ambisonic Volume Adjustment/Panning

In the past, I did record ambisonic sound using a Zoom H3-VR recorder. That did work in a fairly straightforward manner.

What I would like to do next is use a Rode NT-SF1 ambisonic microphone recorded by a Zoom F6. Much like the Zoom H3-VR, it does record ambisonic A in 4 channels which are included in one WAV file.

My knowledge of Ardour is limited, but I would like to use it to run the Rode/Soundfield ambisonic plugin.

What I would need is a professional way to adjust the volume of two of the four channels in the track/WAV import ideally by a set number of dB before applying the plugin. So far, I did not find the right panner or entry field for that. Is there a good approach and/or documentation? On gain adjustment, the manual has region gain and gain envelopes, but that does not seem to address changing gain per channel.

Thanks & regards,

Michael