@CaseySJ Thank you for starting this thread and writing the guid. Ive been able to set up a working 10.15.1 system following your steps.
However, Ive run into some trouble backing up with CCC. Using a 1TB NVMe as startup and an internal SATA SSD, I followed the guide to create a bootable backup of my fresh install and then verified it by booting from the backup drive successfully. Afterwards, I continued setting up my system by transferring apps and data from my old iMac. Later, I ran the CCC clone task again and it appeared to copy the new files then delete all of the files on the backup drive AND the source drive. At the end CCC showed task complete but neither drive was bootable. EFI partitions didnt seem to be affected. Has anyone seen this before?