I was asking about retention and backup full settings of the source backup job, not media pool. But, it seems that you're creating full backup on weekly basis. Then, all you need to create is backup to tape job, specifying the said backup job as a source for it. Set the newly created backup to tape job to process both full and incremental files and to run right after the new backup file appears. This way, once new backup file is created, it will be immediately archived to tapes by the corresponding tape job.
As to media pool, everything can be done with the use of one media pool. So, there is no need to create an additional one.
I have set 'never to overwrite data'
Do you have a requirement to store the data on cassettes forever? I'm asking since with this option in place, the tape mediums will be never overwritten, and you will have to add new tapes in order to locate new backup files.