For meditation, there's a text I've read by a French kind of Catholic aristocrat writer (Alphonse de Châteaubriant) that became hitlerist after visiting the IIIrd Reich, and after WWII started a monastic life in exile in Austria because he was condemned to death in France.
He wrote a lot of mystical things during this period.
One of these is the narration of a personal religious crisis during the 30s, in which he explains how he started to put order in his mind, and the fact that when he read great mystics he found that they were using the exact same method.
I'll try to see if I can translate it, it's pretty short.
As for something tied to meditation, memory and mnemonics are important (when tied to philosophy and objects of Faith especially).
I'd recommend you pic related even if there is an adaptation to make if you are not a native English speaker.
Also, in order of importance :
Mary Carruthers' books, especially :
-The Craft of Thought: Meditation, Rhetoric. and the Making of Images
-The Book of Memory: A Study of Memory in Medieval Culture
Other books by Kevin Vost, especially :
-Memorize the Mass
-Memorize the reasons
(if you're /fit/ : Fit for eternal life)
Also, not as centered on Catholicism yet still important to have informations about the methods :
-The Art of Memory (Frances Yates)
-The Mind of a Mnemonist (Ar Luria)
I guess you can find some of these resources in .pdf but I didn't search and all.
Also, a conference on the topic by Carruthers
https://www.youtube.com/watch?v=Sgv1BMLP-Y8 