I am seriously on the verge on buying VocAlign for this purpose. With doubling, it's no big deal (usually), but when you have 12 or more background voices, it gets tough to fix thimgs manually, either in Melodyne ,or by splitting clips and moving pieces. I would rather push a button, get the the parts aligned, and then nudge a little if I wanted to loosen things up just a bit.
I suppose VocAlign would work with harmony guitar parts as well, but that is not currently a problem.