The G4/G5 Mini guide has gone through a lot more development and will save you a lot of time and effort to get a working install. You should be able to find a G4 at a decent price you could afford. Something as seemingly insignificant as a BIOS version can make a big difference in how well things go. If someone else has already tested and found the best one to use that is really valuable. If you have to do all that yourself it could take a lot of trial and error. The newer the chipset, the longer you should get macOS support without having to keep changing your SMBIOS to something newer and creating new serials to go with that.I am looking at getting one of these hp 800 elite desk minis either g3 or g4.