Dual Mono Setup with HifiBerry Amp

I'm working on a multiroom system based on HifiBerry Amps with RasPi and piCorePlayer (v6.1.0). In some rooms i don't need a stereo sound, only a mono. I found an instruction to split the stereo channels in two independant mono channels (https://www.hifiberry.com/docs/softw...al-mono-setup/)
I did the following steps to get two mono channels:

1. Edit the asound.conf as described above. Over network or directly with the command line.
2. Set the output setting in the Squeezelite tab to "default".
3. Set a name and a MAC address and save the settings.
4. Now a second zone must be applied. Go to the tweaks tab and put in a user command:
   /usr/local/bin/squeezelite -n "Player2" -o card2 -a 80:4::1: -m ab:cd:ef:12:34:60
   Player2 is the name of the new zone and ab:cd:ef:12:34:60 the MAC address.
5. Click "backup" and "reboot" on the main page.
6. Via LMS web page both mono channels could be controlled.

This setup works with AMP2 and MiniAmp.