I was exposed to Mochizuki's sutemi waza early 70-ties by a man called Cleriot from France, he was a Yoseikan exponent, in the same period I have trained extensively with Jacques Normand who stayed end sixties early seventies in Shizuoka dojo. Those people gave me the impression, sutemi waza was (is) a very important item in their training.
In a book written by Hiroo Mochizuki, printed in 1971, sutemi waza is well documented. The uke's for Hiroo are Coquet, Normand and Pons.
Great! Thanks for those additions. So it seems that Mochizuki Sensei really began developing his own sutemi waza in the 1960s or even in the 1950s. I imagine he went to work on it even while in France, in the early 50s or shortly after returning to Japan. Of course, as I said, he had trained with Mifune, so he had probably been doing the judo sutemi for a long time, too.
Another person I could have mentioned in Mochizuki Sensei's development of sutemi waza was Akahori Sensei, who was one of the main judo instructors at the dojo. Very good at aikido, but I mostly thought of him as the judo teacher. He was shown in an early manual on sutemi waza that Sensei had printed.