Confused by the term 'table size' in Redshift.

We have : svv_table_info.size "Size of table in 1MB blocks"

svv_table_info.pct_used "Percent of available space used"

... so I assume that a lot of the 'size' is empty space due to sort keys etc

Then we have this.. https://aws.amazon.com/premiumsupport/knowledge-center/redshift-cluster-storage-space/

.. which uses the term 'minimum' table size. But nowhere can I find an explanation of what they means in the real world ? Is this a theoretical minimum if optimally configured ?

Ultimately I need to find out the basic size of original tangible data without any overheads.

Then yes, how much disc space is it actually costing to store it in Redshift.

So if I took 1TB out of our on-prem database and shoved it into Redshift, I'd be looking to see something like 1TB (data) & 1.2TB (data Redshift overheads).

Hope someone can help clarify