Maybe I minimized the songs that were "bubbling under" the WABC top 14. It might be 10 or more. But they didn't rotate anywhere near as fast as the top 14. The WABC tribute website has access to all the weekly playlists. I think the cut off point on the chart was #14 because WABC didn't want to play a former hit song that had fallen beyond that point.
Let's take the first week of November 1971. The top 14 are listed. Then it lists 17, 18, 19 and 20. And also 35, 52 and 66, along with two "hot prospects" that I suppose had just been released. There were also seven album cuts but I don't think those got played outside of evening hours.
How far back did WABC go for it's "gold" file? Maybe I should have said "recent" instead of "recurrent". I don't think gold songs went back more than five years or so. It's not like some of today's Top 40 stations that will go back to the early 2000s. Playing gold was so infrequent that when WABC played gold it had jingles announcing it.
At least that's how I remember it from my own listening as a kid and hearing airchecks from that era.
You are partially correct. Throughout most of the 1970s, WABC showed only a top 14 list with additional risers being bulleted. During most of the 1960s, it was a top 15 and there are some surveys from the early 1960s (available at the ARSA survey site) that show WABC using a top 30 or more survey. If I remember correctly, it was PD Rick Sklar who insisted that the number of currents being played in rotation should be very low and that they should be played a lot! While I am not into that kind of radio myself, it is easy to understand why he did this once you realize that radio is geared towards the occasional listener and not towards those who listen all of the time--there are a lot more of the former than the latter.