How long does it take to learn Thaumaturgy/Necromancy rituals?

I found in Rites of the Blood on pg.136 that rituals can be learned for free for Tremere/Giovanni/Other as long a teacher is available + other resources (those are not a problem) but it takes time. I wasn’t able to find how much time. That information might have been published in another companion book.

Could you point me in the right direction to figure out how long it takes to learn a ritual based on it’s level?

Would prefer information published in recent editions if available such as Vampire the Masquerade V20 or Vampire the Dark Ages 20. Not just the core books; any Vampire V20 books would do, like Rites of the Blood.