Thanks for the info.You could go for a Cougar QBX for the time being, it's cheap and offers a similar internal design like the NCase.
They aren't still 700 euros, they have been way cheaper, guess they are sold out now. Pretty sure they aren't produced anymore since Navi is going to replace Vega in terms of performance (with way less power consumption and noise). I'd reccomend you to wait for a 5700 XT. Blower Vega 64 are a pain in the butt anyway ?
Yeah, I can't find any cheap blower vega 64 and the other ones are all 3 fans +2,5 slots but at a really good price right now.
I would wait for a 5700 XT but I fear it may not be compatible with the hackintosh.
As of now, Mojave 10.14.5 offers native gpu support for most of the polaris and vega cards.