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having Time Machine and Cloned image on the same physical drive (your first back up drive if I understand what you wrote) doesn't buy you anything. If the drive fails you lose both backups. Use one drive for Time Machine and the other for CCC.
 
That is a viable option, but know, that CCC has to be setup to backup every partition of HDD 1 to HDD 2 (one schedule per partition) and that there should be no duplicate root folder names on HDD 1's partitions.

I have a similar backup plan, though without Time Machine:
I have one 500 GB HDD for my photographs (digital and analog) libraries and editing documents, one 500 GB HDD with my personal video footage in an editing friendly format.
Both 500 GB HDDs get backed up to one 1 TB HDD via CarbonCopyCloner.
And that 1 TB HDD gets backed up to another 1 TB HDD via CarbonCopyCloner.
Therefore I have three copies of my important data.

Also know, that TM on partition 2 will not backup contents of partition 1 (music) or partition 3 (clone) on the same HDD, thus the clone of partition 1 on HDD 2 is the only backup of partition 1 from HDD 1.
 
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