Documentation on spider_casual_read is insufficient/non-existing

It is not clear from this document:

https://mariadb.com/docs/reference/mdb/cli/mariadbd/spider-casual-read/

and KB:

https://mariadb.com/kb/en/spider-server-system-variables/#spider_casual_read

what is the "connection channel" and what settings should be used and at what level for typical use cases:

1. The overall data node is 4 nodes and there are two partitions that point to the same data node.
—
CREATE TABLE spider (
:
) ENGINE SPIDER PARTITION BY xxx (
pt1 ... ENGINE SPIDER COMMENT 'srv datanode1' ,
pt2 ... ENGINE SPIDER COMMENT 'srv datanode1' ,
pt3 ... ENGINE SPIDER COMMENT 'srv datanode2' ,
pt4 ... ENGINE SPIDER COMMENT 'srv datanode3' ,
ptmax ... ENGINE SPIDER COMMENT 'srv datanode4'

)
—

2. Case with four overall data nodes and three partitions pointing to the same data node

—
CREATE TABLE spider (
:
) ENGINE SPIDER PARTITION BY xxx (
pt1 ... ENGINE SPIDER COMMENT 'srv datanode1' ,
pt2 ... ENGINE SPIDER COMMENT 'srv datanode1' ,
pt3 ... ENGINE SPIDER COMMENT 'srv datanode1' ,
pt4 ... ENGINE SPIDER COMMENT 'srv datanode2' ,
pt5 ... ENGINE SPIDER COMMENT 'srv datanode3' ,
ptmax ... ENGINE SPIDER COMMENT 'srv datanode4'

)
—

3. Case where the overall data node is 4 nodes and every partition points to a different data node

—
CREATE TABLE spider (
:
) ENGINE SPIDER PARTITION BY xxx (
pt1 ... ENGINE SPIDER COMMENT 'srv datanode1',
pt2 ... ENGINE SPIDER COMMENT 'srv datanode2',
pt3 ... ENGINE SPIDER COMMENT 'srv datanode3',
pt4 ... ENGINE SPIDER COMMENT 'srv datanode4'
)
—

4. Case where all partitions point to a local table

—
CREATE TABLE spider (
:
) ENGINE SPIDER PARTITION BY xxx (
pt1 ... ENGINE InnoDB,
pt2 ... ENGINE InnoDB,
pt3 ... ENGINE InnoDB,
pt4 ... ENGINE InnoDB
)

So, can you, please, clarify in the documentation, Enterprise or KB, or both, what value to set for spider_casual_read, and on what level, table or global, for each of these 4 cases?