It should be noted that Reghini, who was a member of Ur's group (the best imo he is underrated), expressly said that all real magic (apart from so-called "natural" magic which is not really magic) was doomed to failure, which contradicts the words of most of the other members of Ur.
Reghini writes in his book about Agrippa, quoting one of his letters:
“La chiave di tutta la faccenda la riservo a me ed agli amici [...]. Sarebbe a crime and a public sacrilege that happens to all the coscienza of all. Poiché essa non si trasmette (traditur) con gli scritti, ma allo spirito per mezzo dello spirito si infonde (sed spiritui per spiritum infunditur)”.
in English: "The key to the whole affair I reserve for myself and for my friends [...]. It would be a crime and a sacrilege to publish this affair to the conscience of all. For it is not transmitted (traditur) through writings, but is infused (infunditur) into the spirit by means of the spirit."