I believe Ive read & heard by various sources that it was a 100/1 hard rubber berg with a very hard reed, like (at that time) Brown Box regular Rico 4 1/2 or 5.
I think you can kinda tell its a hard set-up, if you listen closely, esp. in the recordings of the Elvin Jones 1960s period.
I also think I heard the played on a soprano Soloist "G" facing.
I believe Tim Price knew him personally, starting in the very late 60's and could tell us more definitively what he remembers it to be.