Update have 2 rigs currently running 6 1070 running stable. Can't get a 7th card stable, I think it's due to my psu issues with rails. 6 is stable. I was crashing because I think I had a bad gpu. That one card  would run at about 72 degrees when the other 5 would be at 55. Swapped that out and 6 ran fine. Setting a 3rd rig up on a z2 today hope it goes smoothly.