The Hosts seem to like their elves to be in the 6' (1.83 m) range, though they have certainly allowed some shorter actors to be cast.
I agree that the tallest of the elves are taller than that, and I do believe we cast some actors who were more 6'4" (1.93 m) for some taller characters such as Turgon and Thingol.
Really, the problem is that practically all of Tolkien's characters are 'tall', and you can't just cast all tall people for everything. I mean, you could, but then they don't even look tall.
But I do think that there was a general desire to keep the elves tall, so that when we get to mortals, we can make them a little shorter.
As for age, we're trying to focus on actors under the age of 40 when casting elves from now on. Yes, we did cast some older actors for some elvish roles, but we may not have been entirely wise to have done so!
So, for Annael, I would imagine we're looking for someone who is approximately 6', dark hair (or silver wig), and under 40. He would have to be able to portray someone who is betrayed; the scene where the rug is pulled out from under him should convey how shocked he is by the truth. And, he'll have to do whatever 'hypnotized' thing we come up with to show he is not acting under his own will. And we'll want him to have a fatherly aspect with Tuor. Also probably an exiled/slightly wild phase where he's a loner.