Whether you do it in the VH or in Cubase, simply taking the SAME vocal and moving it a few milliseconds isn't really 'doubling'. There ARE some hardware and plug-ins that do it well, but they do a LOT more than simply copy and move in time... that tends to lead to that 'phase-y' or chorused sound that mars that track.

The best doublers constantly move the amount of time the doubled track is in relationship to the original, and also move the pitch around somewhat, so you don't get the phased sound that close moves give you, or the slapback sound that moving it far enough away that it doesn't flange/phase.

But the best 'doubler'? Sing it twice! Work really hard on using the exact same phrasing you did the first take, then chop it up in Cubase whenever it gets a tiny bit too far from the original. A hair of Auto-Tune on the doubled take can help, too.

No school like the old school!