Out of curiosity can you tell me which distro you use and management tools (virt-manager) ?
Certainly. When I first converted the Mac, I used Ubuntu's latest LTS (14.something). The reason: I needed a distro that supported GRUB 2 for EFI boots. I really prefer CentOS/RHEL, but at the time, CentOS 6 was only distributing GRUB 1. Just today, I finally converted it over to CentOS 7 which required breaking out of the Anaconda installer, running parted to delete all existing partitions on the target disk, and then editing one of the Python files on the ramdisk. It wasn't fun, but it worked (bug in RHEL installer. They know about it but don't care).
As for management, I use either virt-manager, or I just edit new XML files and "virsh define" the new VMs.