PBJ-we might be twin sons of different mothers (Dan Fogelberg, I believe). I also got my first R to R in 10th grade, in 1970. It was a Sony 252D, which has long since been worn out and trashed. I still have the tapes I made on it. I also have the tapes my mother player on her Webcor, going back to the mid 1960s. That Webcor was a piece of junk, but the tapes still sound very good, even better than the vinyl versions when I can compare formats. Not bad for almost 50 year old source material.
Unlike you and OBG, I have only one R to R (the Revox) and three cassette machines (NAK CR 3a, B&O 5000 and Kenwood K-1020). The B&O is just plain cool. The decks are spread over several systems, so no need for a patch bay.
OBG-if you have a spare receiver or pre around, might it work to expand your tape loops?