Since nobody's posting, another interesting point of entry is this thread.
https://www.salsaforums.com/threads/old-salsa-photos-thread.42218
I look at posters and try to picture, how the shows were organized from producers/booking agents/audience perspective. I try to imagine what kind of people went there, how much did it cost for them with regard to income. How much they cared about music? How much for other services and opportunities at the venue? If it's in the hotel, was the concert free for hotel guests?
Which artists played together (though apparently some posters are misleading)? Who was promoting them?
How much time did they spend rearranging instruments and how much they actually played? Or maybe they played on the same instruments? A house instruments? There are DJs mentioned, so were there soundchecks on the stage while DJ played? How did that impact quality? Did they talk to audience a lot? How many songs did they perform? Were there many instrumental solos when there were many featuring artists? How many bands from those that performed together also shared a band members? Did they do it to save cost?
I might look up addresses and try to picture how that area looked like.
I look at the venue opening and show start schedules and try to understand what kind of people went to shows, how they organized the rest of their life.
I look at the font size and try to understand why promoter wanted to emphasize one or another artist.
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So I try to find info on internet about these questions and piece the puzzle together.