The 5.1 is recreated from several sources so if you need a 2.0 track, stick with the one that is already 2.0. It is already the matrixed Dolby Stereo that can be decoded into 4.0 tracks by any pro-logic decoder. I personally like doing the same thing, but I always keep the mono soundtrack as it is so unique.
Hi @yotsuya! Please tell me what you like about the mono track? I would not have thought to include the mono track in the final squished file. I have heard it is as close as you can get to the 1977 theater experience. (I saw STAR WARS in 1977 at the Chinese Theater on Hollywood Blvd!) Other than that fact, what appeals to you about it?
Where can I read about the audio-specific things you mention? I haven’t been able to find detailed track notes.