you asked drmdab about modes and bitrates, anyway I would like to comment on this if you donīt mind.
With mode A you get a higher bitrate with about the same robustness of the signal, besides on the transmissions from BNR you can also see that on some transmissions form VT Group originating from the UK, also BBC&DW use it during the day. Unfortunately on your transmissions on 6015 kHz from Issoudun in my location the IR is too long for using mode A, so I would be outside the service area, I can send you some RSCI recordings if you are interested.
Maybe it would work on the US transmissions with the higher frequency.
Concerning parametric stereo, for low bitrates I would prefer mono, but from about 20 kb/s using parametric stereo is OK.