A small suggestion for unison, it would be nice to have a third option, Volume spread or similar...
It would do the following:
The main voice (on uneven voice counts) would have full volume and the others
Would decrease by a factor. So for example with a factor of 0.2 and five voices, the middle voice would be at Volume 1 the two left and right at 0.8 and the two furthest from the middle would be at 0.6 Volume. This would increase the spreading fx, and allow for more natural sounding detune fx, since you can more clearly hear the main voice. With even voice counts simply set the middle two choices to the same Volume.
I hope it is a clear explanation