I received a cactus as a rescue and subsequently found it necessary to cut it into small sections and try to root those. The first of those sections has developed a very bad case of rot. I'm thinking I can make one last attempt to propagate from this section. Even if I can't, I'm going to try because things are looking very grim and otherwise it will just die.
Given the size of these aeroles, what kind of grafting stock should I use? Is there a particular technique that is most appropriate? I have access to lots of tools and can source some rootstocks if pereskiopsis or PC Pachanoi isn't the best candidate.
The gallery of candidate aeroles is here, with my backwards yankee scale for, uh, scale.
https://imgur.com/a/6M7Fr