“I thus decided to designate the 1979 map as the Tauranac-Hertz map”
Your reasoning is impeccable, but the semiotics may not communicate the reasoning clearly. The priority of names may be taken to imply priority of design. (Hertz complains of being “at the arse end of the hyphen”.) I prefer the neutral name “1979 MTA map”, which I believe Tauranac and Hertz ﬁnd acceptable.
You quote from your book, “Conceived by John Tauranac; designed and executed by Michael Hertz Associates” and then …