Hello,
I use 6x the MSI RX470 gaming x 8GB cards. I have a hashrate from 279 sol each cards on zcash mining with ethOS 1.2.0
Total I have a hashrate from 1674 sol.
On stock settings this card makes 165 sol
My power consumption is for the total system 825 Watt from the wall. (including motherboard).  Each card used 130 Watt with overclocking. (Stock is 110 Watt)
I use the next settings for overclocking:
mem :  1725
core:  1240

I hope this is usefull for you.

I use 6x MSI RX470 gaming x 8GB for Zcash mining with ethOS 1.2.0
My settings in ethOS for this card is:
fan (rig-name)    60 60 60 60 60 60
cor (rig-name)    1240 1240 1240 1240 1240 1240
mem (rig-name) 1725 1725 1725 1725 1725 1725
pwr (rig-name)   20 20 20 20 20 20

With these settings I running at 825 Watt at the wall. When I set the core and mem back to default then I use 785 Watt at the wall. (1200w PSU)
My total hashrate is 1670 Sol with these settings.
The temperature from the cards is around 45 degrees.
I think the settings are also working for ETH mining..., you can try it.

GPU
GPU's MODEL NAME:  6x MSI Radeon RX470 Gaming x 8GB
VRAM: 8GB
CORE/MEMORY CLOCK: 1240 / 1725
HASHRATE: 278  (Total: 1668)
MINER SOFTWARE: Claymore
OS: ethOS 1.2.0
TDP(OPTIONAL):
POWER CONSUMPTION: 130 Watt each videocard  (Total system power consumption including Motherboard: 828 Watt)