Here is a quick guide on how to use DXVK in PlayOnLinux 4.2.12
http://www.gamersonlinux.com/forum/threads/dxvk-guide.2540/
I have been playing around with it for several weeks and couldn't get DXVK working. Then I found that PlayOnLinux Wine versions have not been compiled with Vulkan. So I ended up going to Lutris wine versions and it works!
If PlayOnLinux developers can compline Vulkan with Wine and Wine staging, then we can skip several steps and focus on Drivers and DXVK versions.
