Kevin,
You're saying you utilized Slice with a .6 humidity. Was this the first or second humidity? Did you use wrap?
With ZAG, you measure your gains on the first run-through, switch to apply gains, set your center, front, and LFE settings, and then record. You're correct on that.
As far as the "echo" goes, Zeerround's better at asking FFT-related questions. My question is more source-dependent. What artist are you trying to convert? Is this an artist where vocal echo is inherent in the mix?
Did you also try ArcTan with this source?
Thanks for the kind words. That Zeerround is a surround genetic freak.