The form will have had is the future perfect, which allows you to describe an event that will be complete at some time in the future. This distinct from will have, which is the simple future and describes an event that will occur in the future.
- The arriving batch of Russian conscripts will have had limited training.
The arriving conscripts will have already completed training, which was limited.
- The arriving batch of Russian conscripts will have limited training.
The arriving conscripts will either:
- have already completed training, which was limited, or;
- be given training, which will be limited.
The context definitely requires that the first meaning, not the second, be conveyed.
1) It has been a long time since I visited you (at the hotel).
I visited you at some (distant) point in the past.
2) It has been a long time since I used to visit you (at the hotel).
In the past I visted you on a regular basis, maybe once a week. At some (distant) point in the past, I broke with that habit.
3) It has been a long time since I have visited you (at the hotel).
I visisted you at some (distant) point in the past. I probably have visted you more than once, but that doesn't mean it was a habit.
So, yes, 2) and 3) could have a similar meaning, but 2) really draws attention to the fact that the visiting was happening on a regular, habitual basis, and it is the habit that stopped a long time ago.
Just for illustration, let's look at a different example.
Suppose I used to live in city A, but I have now moved to another place. While I lived in city A, I visted a certain restaurant once. Also, I was a regular at a bar (I was there almost every day). There was a cinema too. I went there a couple of times, but I'm no great fan of the cinema.
Now, after some years, I could say:
It's been a long time since I visted that restaurant. It was a really great experience though, maybe I should go back there some day.
It's been a long time since I used to frequent that bar. Nowadays I just drink alone, at home...
It's been a long time since I have been to that cinema. I don't know if that nice girl still works there.
Best Answer
Definitely the first if you are trying to convey to someone that you don't have the information, but will tomorrow. The second doesn't really work at all (I'm guessing). "I will have had" implies you no longer have the information.
To get a sentence more similar in theme to your second, you could use "By this time tomorrow, I will have already gotten/received/obtained the information you need".