Re: right way of doing sitting kokyu-ho
In my limited experience, the center-to-center connection in sitting kokyu-ho is important. After taking uke's balance, it should be the movement of your center to the side that causes uke to move to the side and down.
The following books have good explanations and solutions for various "problems" in sitting kokyu ho:
(1) Total Aikido by Shioda Gozo
(2) Living Aikido by Bruce Klickstein