Looks promising, though I thought it was gospel not to use SATA power because of the cards drawing more power than it's rated to handle?
Depends with which GPU. In most cases, there is absolutely no problem using SATA. the sata to molex adapters are the problem though. I dont know how much VEGA pulls from sata but I have some on SATA and they are cold to the touch, no worries there. Of course only use one or two per string, never more...