Create consistent, self-contained incrementally merged backup

We use the following script to create a self-contained, consistent full backup --

run {

        set nocfau;

        allocate channel ch1 device type disk format '/backup03/%U';

        allocate channel ch2 device type disk format '/backup04/%U';

        backup as copy database plus archivelog;

        backup as copy current controlfile;

}

We are attempting to develop a similar script but one that does an incremental backup and merge --

run {

      set nocfau;

      allocate channel ch1 device type disk format '/backup03/%U';

      allocate channel ch2 device type disk format '/backup04/%U';

      backup incremental level 1 for recover of copy with tag 'tag' database plus archivelog;