You may use my specs and adjust accordingly, maybe it was not so good but at least it's a good place to start. It takes few days for me to found sweetspot for my card.
Ignore the temp as it is enclosed in CPU chassis without enough ventilation, I am waiting for Scythe fan to arrive to blow the heat away.
Using Uber-Mix Extreme v3.1 from OC.net
777000000000000022CC1C00AD615C41C0590E152ECC8608006007000B031420FA8900A00300000010122F3FBA354019
You may try using your own timing from 1:1750 and paste it to 1:2000 , result should be similar.
MSI Afterburner :
-96 mV core voltage limit
+30% Power Limit (well I guess this doesn't help but I just put it in)
1192-1198 MHz core clock
2075-2085 MHz memory clock
If you think that the core clock is not important for ETH mining, then you are dead wrong. So don't set the core clock too low either.
For Claymore configuration : use -asm 1 and -dcri 33 , i seen much improvement on compared to the screenshot above with ETH on 30.4MHs and DCR on 1000MHs
Good luck and if you think my post is helpful, feel free to donate some ETH/DCR for me!
ETH : 0x2345988e664AB0b2608185578623c5f252a40a17
DCR : DsoL8UaDLdjAsPZCAb6H87RDNtpPRSMnDWu
Sapphire Nitro+ Limited Edition RX 580 8G (Samsung) over 30MH/s @ 0.7875V: https://ottrbutt.com/tmp/580UV.jpg (NSFW)