I2S output from DAC+DSP (doesn’t work with standard or custom profile)

I’m on the cusp of completing an awesome portable party system built around Hifiberry attached to a Tham 12 sub and a massive synergy horn designed by Scott Hinson but got stuck at the last stage!! I’ve got a PCM5102 Dac board connected to the I2S output pins of the DAC+DSP. The sigma studio project associated with the standard Dac+Dsp profile v12 looks like it should work when the Dac is connected to SOUT2 as the 3rd and 4th channels in HifiberryOS are routed to serial outputs 17 and 18, but it doesn’t! I got it working by updating the serial port settings and routing configuration in the sigma studio project to use an ASRC for output, without needing to change the schematic (because channels 3 and 4 in hifiberryOS are also routed to ASRCs) and I get sound from the DAC, but then the HifiberryOS controls don’t work properly. I tried to fix that by using the process in the Hifiberry GitHub repo to create a custom profile, and all seems ok but when I re-load that profile from the GUI the Dac stops playing. Seems like 2 possible problems / solutions: 1) are the serial port settings and routing configuration included in the custom profile updates or is there something else I need to do to make sure they are part of my custom profile? 2) is there a way to get it working with the standard v12 (or v13 or v14) profile? I appreciate any help anyone can give!