What is the purposes of the past perfect tense in the paragraph?

Question

A third coatless man wiped his bald head with a striped kerchief while he growled at them.

    "Easy with it. Easy, I said! You motherless weasels knock a lens out of alignment, and I will knock your brainless heads backward to front. Fasten it tight, Jol. Tight! If it falls while the Lord Dragon is looking through it, you both had better jump after it. Not just for him. You break my work and you will wish you had broken your fool skulls."

    Jol and the other fellow, Cail, worked on, quickly but not very visibly perturbed. They had had years to grow used to Kin Tovere's way of talking. It had been finding a craftsman who made lenses and looking glasses—and his two apprentices—among the refugees that had first given Rand the idea for this tower.

_{—from The Fires of Heaven, by Robert Jordan.}

When I learned English Grammar, I was told that the purpose of using Past Perfect tense is to imply the time between the actions. However, I am confused in these paragraphs.

I was confused by 3 sentences:

1) "They had had years to grow used to Kin Tovere's way of talking."

What is the difference if I change it to "They had years to grow used to Kin Tovere's way of talking"? How about "They had grown used to Kin Tovere's way of talking."?

2) "It had been finding a craftsman who made lenses and looking glasses—and his two apprentices—among the refugees that had first given Rand the idea for this tower"

I assume by using the word "find", the writer meant "discover". But you can't use continuous tenses on "discover" because the action cannot be prolonged.

3) Finally in the last sentence, the phrase "that had first given Rand the idea for this tower" does not have a counterpart in the correct of Past Perfect tense.

As far as I read, this is how Past Perfect was used - to describe one thing happened before another.

In the context of the text, obviously Rand found the craftsman before he had the idea. It makes no sense to me to use past perfect tense on the clause "that had first given Rand the idea for this tower."

Could you please help to answer my questions? I really have difficulties understanding English tenses because they are so complicated.

Answer 1

A primary use of the Past Perfect tense is to relate an event A that occurred prior to some other event B, where event B is already in the past. In other words, Past Perfect requires 3 time reference points:

      A       B       Now
  ----+-------+-------|-------
  past                    future 

(See this question here for details on how the various English tense constructions refer to different points in time.)

For your question 1, the events are:

• A: Jol and Cail grew used to Kin Tovere's way of talking (some years before point B)
• B: Kin Tovere was berating them as quoted
• Now: someone is telling you about the beration

If you change this to "they had years" instead of "they had had years", you are changing it to a simple-past construction, which changes the meaning to "someone is telling you that (as of the time they are being berated) they will have years to become accustomed to Kin's way of talking."

If you drop the "had had years" bit and change it to "they had grown used ...", then you have not changed the primary meaning of the sentence, you have only lost the bit about how long they had been working with Kin.

For question 2 & 3, the events are:

• A: Rand discovered a lens craftsman
  • this discovery gave him the idea for the tower
• B: The tower was being built by Jol and Cail under Kin Tovere's direction
• Now: someone is telling about the beration that happened during the construction of the tower

The construction "It had been finding a craftsman" is not past perfect continuous, but rather a past perfect + gerund: "It had been (X) that gave Rand the idea", where (X) = "finding a craftsman who made lenses...". This particular (X) is a very long phrase, so it can be easy for a non-native reader to get lost trying to keep track of it.

For question 3, I happen to agree with you that the past perfect is not generally necessary; we've already established the timeframes with the introductory clause "It had been (X) that", so we can conclude the sentence with a simple-past construction: "It had been (finding a craftsman blah blah) that first gave Rand the idea for this tower." However, some people feel that keeping the second clause in the same tense as the initial is preferable to make the linkage clear, especially in cases (such as this) where the intervening phrase (X) is very long.