Are you talking the 'ooooohs'? Those are definitely panned wide. Again, I think they are high passed quite a bit. And perhaps some reverb to glue them together.

My only attempt at 'oooh' bgvs is here at about 1:35 to the end of the 2 minutes:
http://rockstarnot.rekkerd.org/songs/newer/rockstar_not%20-%20The%20Golden%20Age%202%20minute%20cover.mp3

It's a cover I made for a contest at KVRaudio.com We were supposed to disguise our identities. I tried to be Beck Hanson doing his magnificent 'Golden Age' song. Reference here: https://www.youtube.com/watch?v=jFIVUpSpMJw

When I listen back to the Beck track, I would have high-passed my vocals just a bit higher on the lead vocal. I also have never figured out to do the 'noise' effects throughout the song. I think I had too much swing in my acoustic playing, but I do like my double-tracking of the acoustic guitars compared to the middle-focused acoustic on the original. One thing you can also do is highpass the reverb, so you don't muddy things up too much.

Take a listen and see what you think.