What I've found is that if one borks an install, it kind of ruins the USB installer and you have to really start over, even clearing what seems to Optimized Defaults. This time, I opened the MultiBeast package and installed Clover from there to be sure everything matched. -This was the first time I did that. EFI Mounter v3 was not working on first reboot, and I didn't see any of the MultiBeast patches anywhere (neither EFI nor S/L/E) so I figured I was gonna be a Windows 10 guy on this machine when I restarted. But then, it just worked. So, I did what you said and I'm cloning the HFS+ Fusion drive to an Angelbird HFS+ SSD. If the clone takes, then I'll proceed.
Okay, so I have a working 10.13.6 APFS working on an SSD. -The APFS No Convert command still doesn't work. This build, I only used MultiBeast and Migration Assistant -I did not use Clover Configurator. My trick is to go into the BIOS screen and make certain that the SATA boot priority is always the UEFI part of my SSD. If you've used other drives (disconnected or not) it may take a few tries to get the right SATA device in this MOBO's "two-choices only" design.
FWIW, "Optimized Defaults"
don't always stay that way and are not visible in the BIOS setup after you've attempted a build, so select "Load Optimized Defaults"
every time that you attempt a new install. But hey what do I know? I've been trying this for way too long now.
What I'm wondering now is: Should I go into BIOS and delete any other non-HD specific
BCFG entries that are pointing to anything other than to my newly-minted installation?