I was watching
https://www.youtube.com/watch?v=IyHKZtCbbks regarding vocal doubling without actually re-singing the lead vocal, and wondered if there was a way to do this in Sonar. Basically, create a copy of the vocal, slide it backward by a few milliseconds, then automate a delay ... randomly ... so that sometimes the copy is a little ahead of the original vocal and sometimes a little behind.
I don't think that the VX-64 Vocal Strip doubler does this automatically, but maybe it does. Who knows.......