Gojushiho-Dai & Gojushiho-Sho
When I studied Goju-ryu I was taught these as Shorin-ryu forms that my instructor happened to know (because he liked performing Gojushiho-no-sai as a weapons form). In fact I learned Gojushiho-Sho, then Gojushiho-Ni, and then Gojushiho-Dai. I was told that Dai meant that it was a greater, ultimate, or combined version of the first two. I was a brown belt and it wasn't in my main system so all I can say is that I didn't see a sense in which it was greater.