I just want to thank everyone for being so helpful in this thread. Special thanks to Hellae for his reddit guide and Oldcomer's hardware for his YouTube guide. Just set up my two rigs today running 8 Vega 64s. I am at a combined 15300-15600 hashrate (pool just shows random numbers but calculated total hashes over 7 hours turn out around these numbers).

Running fine for 7 hours. Each system is consuming around 700watts from the wall, one has a killawatt and the other the Corsair RM1000i with Corsair link showing 700W and 93% efficiency on 230v. Hashrate seems a tad low but I had to leave shortly after putting them to work so I had no time to tinker.

One has a running monitor plugged in but I started the second one through TeamViewer (had disconnected the monitor while off) and seems to be running as well as the one with the monitor, maybe HDMI dummies aren't required after all!. I still ordered two and I am waiting for them. Both have onboard gpus as primary. I got two i3-4170s just because I might use them for other projects in the future (AES-NI support). 1000watt PSUS seem just fine so my advice is buy them if they are cheap instead of 1300+.

Have fun, I am!