Anyone ever use Elastique Pro Formant for vocal retuning?

I’d like to retune a vocal but (unlike VariAudio) preserve the formants. Does anyone think something like this might work? …

Starting with a vocal at 100 BPM which we want to lower the pitch by 200 cents (i.e., the original pitch is 12.25% higher than the target one):

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  1. Increase the tempo track to 112.3 BPM (12.25% faster) while keeping the same pitch and formants using Elastique Pro Formant Pitch, kind of like in this video http://www.youtube.com/watch?v=jeFdSDsjyu4&list=SP43D4D4C9D4213E3C&index=8&feature=plpp_video (except for some reason they used EPF Timing instead of Pitch there). So now it’s at the same pitch but 12.25% faster, formants preserved (i.e., no chipmunk)?

  2. Switch to Elastique Pro Formant Tape.

  3. Decrease the tempo track back down to 100 BPM - so it’s at the original tempo, but now 12.25% less in pitch (200 cents) than the original - but with preserved formants.

Not sure about the math involved, or the choice of EPF Tape vs Pitch - what do you guys think? If you think it’s doable, I’ll try it out this weekend to see how much quality of the vocal is affected.

Thanks for any thoughts -