http://www.youtube.com/watch?v=a3jdHtpIuNM
I Want it All - Queen
Those vocal harmonies gave me chills, just amazing!!

I've made some modest attempts at this kinda thing but it takes me ages to get the phrasing and pitch right. I've also tired tuning the vocal tracks (with Melodyne) but it seems to make it too artificial sounding.
One thing I noticed is that: the harmonies are quite loud in the mix. I've noticed the same thing with Michael Jackson's harmonies too. Like here: http://www.youtube.com/watch?v=pEEMi2j6lYE ...difficult to hide problems, at this level.

Anyone got any tips on how to do this (& mix this) well?
Stuart