i took both recordings (he played it twice in the seminar) and what i did was i separated each of them into stems of sort using AI (basically i was left with 2 drum tracks, 2 vocal tracks, 2 bass tracks and 2 tracks with everything else).
after this, i then took for example, the isolated vocals of the 1st and 2nd recording, then balanced them to create a stereo sound to it. i did this for all the tracks that i had on me to make the best sounding mixes i could.
after this, i went through each of the tracks to remove any imperfections, like coughing or rustling by listening to both versions of the track, to try and get the cleanest version of the song there can be. i then did my own stuff with balancing every track differently to make it sound as good as possible.
i dont think this will be done like this again as having 2 different recordings of the same song with both Chicago 1945 and Dreams Away is insane.
hell, in my version of chicago in the intro you can hear the snapping of a camera, i never heard it until i did my version.