If you must have the front mic and PCI working in your build or you haven’t installed macOS yet, I’d suggest a clean install of Mojave or High Sierra by following his guide. He has used techniques from the laptop forums, mainly Clover UEFI Hot Patching to avoid the need to statically patch your DSDT for ALC221 audio, USB, the front mic jack and the PCI slot function. Note that there are 3 available PCI slots in the 8300 Mini-Tower, 1 in the SFF.
The single PCI slot (SFF version) didn’t work and the front mic jack also did not work.
In the past few months community member Sniki has purchased an HP 8300 SFF PC and worked out all of the minor problems that still exist even after following the Sierra/High Sierra guides. Building a CustoMac Hackintosh: Buyer's Guide
