I manage about 32 MH/s with my 1070's (and approach 1.5 GH/s all combined in several rigs).
With the 32 MH/s rate, what should I expect that to translate to in terms of mining Zcash?
ETH hashrate does NOT translate to ZEC hashrate, cards vary.
Most GTX 1070 manage 400-450 sol/s on ZEC - but compare to a GTX 1080 that manages HIGHER hashrate on ZEC but LOWER hashrate on ETH than a GTX 1070 does.
What you're going to run into though is that ETH and ZEC are the cores of the "basket" of profitable coins to mine - they're going to show similar profitability on the most common cards that are used on both, as a lot of folks swap between the two (and the other "basket" coins) seeking the highest income.
In my particular case, none of my NVidia cards are working "common" cryptocoins at all, I'm at a point I can afford to take a less-than-optimal income while doing what I WANT to do with my rigs (like Moo Wrapper, where I've been the #1 "individual" producer for a couple-three weeks or so).