This might help a little,

The Situation of Karate Overseas: Mutsu Mixuho Shihan & American Karate by Ohgami Shingo.

In the “Fifty Year Anniversary” publication of “Keio University Karate Club” it describes Funakoshi teaching Gojushiho 1 Feb. 1929, and his assistant, Ohtsuka Hironori, teaching Unsu (10 May) the year before. … (However, there’s also one more issue to consider which supports the rumor he leared the kata from Mabuni..)
victor smith bushi no te isshinryu offering free instruction for 30 years