I updated directly from High Sierra via Appstore, and despite my old hardware, everything is OK.
The 2 little problems I had were :
- my High Sierra was on a HFS+ filesystem, so I didn't have apfs.efi in CLOVER/drivers64, which made it impossible to boot
- my core2quad doesn't have SSE4.2...
I'm running a Quadro K2000 on a Sierra Hackintosh.
The only thing I had to struggle with was the Mac model : my previous MacBook3,1 didn't see the card, I had to switch to iMac14,2. Runs fine, with or without Web drivers.