Thanks for taking a moment to reply, avw. Sadly, I haven't found any successful passthrough stories myself.
My VM Configuration:
bios: ovmf
boot: order=scsi0;ide2;net0
cores: 8
efidisk0: local-lvm:vm-109-disk-1,size=4M
hostpci0: 0000:04:00,pcie=1,x-vga=1
ide2...