How long was Saber waiting for Shirou after she died?

Question

Regarding the question that was asked before:
Do Emiya Shirou and Arturia ever meet again after Fate/stay night?

In the Visual Novel of Fate Stay/Night Realta Nua once you have seen all 5 endings a new ending appears accessible from the title screen call -Last Episode-, this is in 2 parts, a Monologue of the Fate Route and a second part where Arturia is hearing from Merlin about a miracle achievable by 2 people, one who "wait endlessly" and one who "pursue endlessly", eventfully the pursuer will stop when they reach the waiter.

What Merlin is referring to is Arturia waiting and Shirou pursueing, eventually Shirou reaches Avalon where Arturia is sleeping and the 2 finally reunite, it's not entirely sure how long it took Shirou to reach Avalon however considering that Avalon transcends all magic including the 5 Magics it must have taken an eternity for Shirou to reach.

Obviously if it took them an eternity to meet, it's common sense that it never happened.

So my theory is that there are two options for this occasion:

1. The author's definition of eternity is something different from what is known to the public.
2. That it was some sort of an inside joke to troll the audience who desperately want to see them reunite.

Is there any official statement about how long eternity is according to the Fate Stay/Night series?
Are there even any clues on which to base some sort of speculation on the matter?
Or maybe the light novel perhaps mentions something about it.

I really want to know how much Saber had to suffer in order to finally meet with Shirou.
(IMO after all she's been through, she has suffered quite enough already).

Answer 1

Avalon is

the domain of fairies... the unreachable utopia that Arthur dreamed of and was said to have gone to after her death.

In the Fate Route, after Saber vanished and returned to her own time, we see a shot of Arturia and Bedivere. It's assumed that from Arturia's line

I think I will sleep much longer this time...

that this occurs after Bedivere third and final attempt to return Excalibur to the Lady of the Lake, as in the previous two attempts, when he was ordered to return the sword, he lied about returning it, knowing that by doing so Arturia would have died. So Arturia died and went to Avalon. Given it's a utopia I don't think Saber would be suffering.

Now Shiro is shown at the end of -Last Episode- to be hugging Arturia and he wa wearing the shroud Archer wore (though now in a different style), so they did meet up. This is why -Last Episode- is seen as the True End of the Fate Route, because Shiro and Arturia are finally together in the end. However, because Avalon transcends all magic, including the 5 Magics, of which The Fifth's domain is suspected to be time travel (but Touko says The Second governs time travel, so I am assuming that Avalon transcends time, or at least out conception of time), so despite the fact that Arturia died long in the past before Shiro was even born, we can't be totally sure that she waited the same equivalent amount of time for Shirou to even be born.

Shiro may have died to before being reunited, or he may have extended his life as some Magi do (without becoming a Dead Apostle). There's a series of H Dojinshin (fan made) which would assume that little time has passed since the time Shiro went to bring Arturia back. (One set has him and Arturia have sex in Avalon when they reunited, while in the next set, they are back in Fuyuki living together with Rin and Sakura visiting).

To my knowledge, it's not indicated how Shiro got to Avalon since we only know the conditions of the Miracle Shiro and Arturia achieved. I used eternity as a means to indicate an immeasurable amount of time, since given Shiro's Magecraft abilities, had he developed something to allow him to reach Avalon, it would have taken him a hell lot of time. After all, the ultimate ambition of every Magi is to reach the root, which can take generations to complete, since it took that long for the Tohsaka's to get close to properly using the Second Magic.