pere is best for seedlings- graft them while they are quite young. i like to graft them while they are still in their initial seedling growth spurt (first week or so of life)

small pups etc- best on other san pedros. the pc clone makes great grafting stock (as it is otherwise almost useless) other columnar cacti can be effective as well.

 

(i've posted teoz' book on grafting in another thread somewhere- it is a great resource!

here it is: Grafting Book L.W. Grafting Bible - Cultivation - Welcome to the DMT-Nexus