Why is in this in Feature Reqest forum? 8)
Firefly only supports WMAL on Windows, since there is no complete reverse engineered WMAL code out there to use on other platforms. So, if you want to use Lossless… you’ll need to convert to something like FLAC. Avoid uncompressed .WAV, simply because there are no standard tags in .WAV files.
Re: changing your MSS… sorry, someone else will need to help on that.