How long would it take to teach the Jesus traditions to new tradents of the oral tradition?

Many who theorize concerning Gospel origins claim that the material which was ultimately published in the four Gospels was preserved almost exclusively as oral traditions, carefully tended by local tradents, until the Gospels began to be published thirty to fifty years after the ascension. For example, Richard Bauckham contends that > Of crucial importance for our whole argument in this book is the role of individual authors and tradents of Jesus traditions. We have suggested that the traditions were originated and formulated by named eyewitnesses, in whose name they were transmitted and who remained the living and active guarantors of the traditions. In local Christian communities which did not include eyewitnesses among their members, there would probably be recognized teachers who functioned as authorized tradents of the traditions they had received from the eyewitnesses either directly or through very few (authorized) intermediaries.1 Accordingly, how long is it theorized that it would take to teach the Jesus traditions, such as what would one day be contained in Matthew's Gospel, to new tradents who would be responsible for accurately preserving such via oral tradition methods? [Reference to a book/article on the topic would be greatly appreciated.] On Paul's second missionary journey he makes it out to Macedonia (Acts 16–17). However, his visits to Philippi, Thessalonica, Berea, etc. are characterized as being both brief and mostly evangelistic, rather than instructional (i.e., training a tradent). Relative to Thessalonica, Acts 17:2 indicates that Paul reasoned in the synagogue for a mere three Sabbaths; although, Paul's epistles suggest that he was in the city for more than two or three weeks. Even if for a slightly longer period, Paul's letters from Corinth applaud the Thessalonians for their grasp of the traditions (2 Thess. 2:15) and their dissemination of the word (1 Thess. 1:8). But was he there in each of these cities long enough to train up a tradent? > To this he called you through our gospel, so that you may obtain the glory of our Lord Jesus Christ. So then, brothers, stand firm and hold to the traditions that you were taught by us, either by our spoken word or by our letter. (2 Thessalonians 2:14–15 ESV) Am trying to draw a comparison between how long it would take to help someone accurately memorize a set of material akin to Matthew, without recourse to a written document, as opposed to simply making a copy of a document. It would seem much more effective to instead leave behind a copy of a Gospel, given that Matthew could be copied within a week. (A related question: https://christianity.stackexchange.com/questions/105788/what-percentage-of-the-1st-century-christian-population-served-as-authorized-tra) P.S. I do recognize that some scholars deny that there were formal tradents or that anyone necessarily preserved anything accurately. ____ 1 Richard Bauckham, Jesus and the Eyewitnesses: The Gospels as Eyewitness Testimony, 2nd ed. (Grand Rapids, MI: Eerdmans, 2017), 290.