The overnights on WGN weren't so much classical as "light music," perhaps some standards, easy listening, and "classical crossover," from what I recall in the early 1980s. Jay Andres, I believe, was host. I think it used to be 5 or 76 night a week, and transitioned to weekends only after WGN went heavier with talk programming. Then evaporated a couple of years later. John Doremus also hosted a show like that. I think he syndicated it to several outlets around the country on LP discs, who could opt for variable length of the program to air.
I, for one, would love to hear airchecks of that again. Anybody got any links? It was dreamy, late night music, and took the atypical step of seguing several songs in a row without any DJ patter. Ultra-relaxed hosting, with long, well-timed pauses. KMOX St Louis had a similar show, and they and WGN were classic DX material with the overnight music shows, but it would probably make you drowsy if on a long haul drive overnight.
I don't know of anyone doing that kind of radio anymore, apart from a few imitators from Moody Bible Institue and Wheaton who took that style for half-hour nightly religious shows "Nightwatch" and "Nightsounds." If they're still around.
