2 rigs with 12 gpus well optimezed (RX 580 and RX 570) doing 31,3 average mh/s, is doing around 376 mh/s. those rigs are using around 1800w from the wall.
with a "optimized" 12x RX580 rig 5 of my cards are doing 32,4 mh/s at 1240/2250 868mv. Are you sure what you are saying? i don't think so.
It's widely proved, that the best ratio performance - power consumption is 1240/2250 at something around 850 to 878mv depending on how good your card is.
i don't think it's wise for you to talk about "optimization" without actually pulling out numbers to discuss.
I posted my numbers for you earlier , as a example how ETH mining is still profitable for me
Thats a 12x RX 580/8GB cards In my example it was ETH11 rigs To refresh your not super strong memory read this
Numbers, Pictures included
Oh BTW your math is awful on your calculation about E3 and a 0.07$ electricity price
You calling members , ppl stupid bc they still mining , but you can not calculate how much income one E3 can generating for someone who is paying 0.07$/kWh
Should i call you stupid ? no im not calling you stupid just saying ...Your 12x RX580 rig optimized and still pulling 1800 watts ? work on that optimization a little bit more and get some real time knowledge about how to mod your bios with hex editing
not just paste and copy mem straps you going to be surprised how much extra watts you can save , but you need a real bios mod Posting pictures again for you , just for you
I hope its helping you to understand some ppl more lucky , or more ? knowledgeable ? about "optimization" Just bc you are not capable to do something its doesn't mean its impossible 
