How to time MIDI notes that generate harmonies in plug-ins?

Hi - Hoping someone with experience using MIDI notes to generate harmonies in a plug-in might be able to help me out a bit …

For studio work, I’m looking at Nectar 2 as a possible way to add harmonies to a vocal line in my DAW. I have a MIDI keyboard, and Nectar 2 is built to listen to the keyboard MIDI notes and generate vocal harmonies from them.

I have tried that in the past with a hardware unit generating the harmonies (TC Helicon VoiceOne, FWIW), and found that it was very hard to get the timing of the MIDI notes just right regarding the original audio track vocal note. If the MIDI note start was a smidge too early, the harmony note would start too soon, affecting the previous lead vocal note incorrectly; and if it was just a tad too late, a little of the original vocal pitch would be audible before the harmony kicked in. Sometimes it took forever to drag the MIDI note start to just the right position …

To be honest, using this method I never was able to figure out how to get the MIDI timing correct without spending forever and a day. This was a few years ago, and at the time the TC Helicon support guy said there was no other way to do it. So I abandoned that, and for the past few years I’ ve gotten the job done other ways (like actually singing the harmonies, egads; or using VariAudio to drag up, etc.). But I’d like to see how good Nectar 2 is at that task, so I’m back to square one again - wondering what the best way is to figure out how to time the MIDI notes properly.

Can someone give me some guidance on this please, is there perhaps another way to get the job done? Any answers, Nectar 2-specific or not, are much appreciated!