How to get a consistent export with Oracle Data Pump

Rather than using notepad as an intermediary, I expect you'd be much better served simply using the SQL*Plus COPY command, i.e.

COPY FROM source_table@source_tns_alias
       TO destination_table@destination_tns_alias
   CREATE dest_table_name ( column_list)
    USING SELECT column_list 
            FROM source_table_name

will copy the contents of SOURCE_TABLE at SOURCE_TNS_ALIAS to a newly created table DEST_TABLE_NAME at the DESTINATION_TNS_ALIAS. There are also options in the COPY command to load data into an existing table.

If you create a new APEX workspace it should offer to create it in a new tablespace. Alternatively, fire up SQL*Plus (called the Command Line Interface in XE) and use the CREATE TABLESPACE command.

That said, given the 4GB limit, for a home install I resize the USERS tablespace to the maximum and just use that. Too annoying having reached the 4GB max and having space available in tablespace_a and not being able to expand tablespace_b when you want it there.

In theory you can shrink tablespace_a but that only works if the free space is at the end and not at the start or in the middle.