https://www.americanradiohistory.com/ is a treasure trove of old magazines. It is also interesting for me to be able to see the ones from other countries like the USA and Australia. I wonder if there is an equivalent site for HiFi, although until Home Computers started to become popular in the early 1980s, audio projects were a large proportion of the Electronics magazines articles and projects.
Success With Cassettes from 1986, from the Gavin Report for radio stations. This is a very basic outline on what to look for in equipment and tapes for one of the most demanding applications. I'll have to pull out my very old TDKs and see how they held up over the last 30 years.