if you want a fixed number of increments in each set, then choose "Full backup
+
If you want a fixed number of increments, less than a multiple of 7, in each set, then choose "Full backup
−
is allowed on" = Anyday.
+
is allowed on" = Everyday. eg Daily backups in each set = 6 will result in 1 Full backup and 5 incremental backups, on each full backup all backups are deleted including the incrementals.