The koryu no kata in the Tomiki system is not known in depth by many Tomiki aikidoka.
Since the Koryu Go Shin no Kata aka Koryu Dai San is a major requirement for Dan tests in the J.A.A what makes you say the above?
You mention Koryu Dai Roku. This is interesting as I have it from very good authority that Tomiki saw only one kata as Koryu (i.e. the Go Shin no Kata) and did not want students to merely memorize a large set of kata techniques (a la Koryu Dai Ichi, Ni etc.) without depth, but instead to study the Koryu Go Shin no Kata deeply to understand the classical martial reality of his method.
Just a thought based on recent discussions with a J.A.A. shihan.