When Ohba sensei was around, he suggested people to study the sword to broaden their view on aikido.
The tandoku undo is in the history of Tomiki aikido changed. If we see the Tomiki movie Judo Taiso, he is doing it in a slighly different way. He is also doing more movements then the current JAA way.
When Senta Yamada came to the UK, he thaught already a revised version in the beginning 60ties. Also the names of the movements is changed. The current JAA tandoku undo is concentrated mostly forward, the old way also included to the side.
In the Tomiki movie we also can see a happo undo;
Why they changed, maybe under influence of tanto randori (?)
IMO the tandoku undo is a multipurpose set of movements and to understand someone has to explain what you are doing. I remember someone from the UK who said : those waving with the arms just like a policeman, that was his interpretation of tandoku undo