Chris it is interesting there is no mention of Tohei sensei by Tamura Sensei as this comment by Stan Pranin on his visit to hombu and his interaction with Tohei has always mystified me!
"As a result, I was called to a room on the second floor of the dojo late in August. Present were Tohei Sensei, Mr. Tamura and myself. I was told clearly that I was considered to be a student of Tohei student and as such was mistaken to have trained with other teachers during my stay in Japan."
This would suggest that Tamura Sensei was aligned with Tohei Sensei but certainly didn't aspire when Tohei Sensei left the Aikikai. But it does suggest the two were close around that time and given that Tamura Sensei arrived in Hawaiii with both O' sensei and Tohei Sensei that he would have worked closely with Tohei Sensei as well!
Also I believe that Yamada Sensei held Tamura Sensei in such high regard ( given the role of Yamada Sensei in Tohei's split ). The statement above doesn't make sense or have I misunderstood something?
At the time, Tohei would have been the boss, Tamura his junior, so it's not unusual that he'd be accompanying Tohei in a Japanese company structure. I don't know whether or not Tamura was aligned with Tohei or not - but it may be that Tohei thought or assumed that he would be, similar things happened in other cases that I'm aware of.