I would suggest that O Sensei would hold the real sword /bokken in the same manner. Check out some Batto ho stuff on Youtube.[not O Sensei ]Possibly Biran Online may have some clips. Hope you are well, Cheers, Joe.
Is Muso Shinden ryu aikido? Does it share the same principles? Do you have riai between your batto-ho and your taijutsu-practice?