You might check out the
Aulani Villas and Views thread here on the DISboards. The first post has a list of rooms submitted by people that have stayed there and submitted view photos. There are links to the photos using the room number. The thread also has a lot of information about Aulani.
As to which tower to select, I would just make sure you have one that overlooks the Waikohole Valley--the lazy river and main pool area. If you want a sunset view you would want to be in the Ewa Building. The rooms nearest the lobby in Ewa have the straight balconies which are larger than the angled balconies. I would definitely ask for a high floor.