gbentley
I think you meant this
http://wiki.contribs.org/Backup_with_dar#Backup_disk_size_limits_workaroundFull daily backups and delete the old first is the obvious answer for you.
For that "smallish" amount of data, then doing a full backup every day is OK timewise.
You could configure backups for a full every month and then incrementals every day in between.
If you swap the backup disk every so often, then change the one month frequency to whatever time period it is that you swap disks eg weekly or fortnightly etc, but you will be in trouble if you do not swap the disk on the correct day of the cycle.
You can restore from any day's backup, or the most recent backup, or do partial restores.
Given the size of the backup disk, you will still have troubles if you only use one disk, so you will need to implement the fix suggested (ie delete first before new full backup starts). It's easy to set the cron job to run every day, if you do a full backup every day.
Given that you will have ongoing hassles with full/incrementals & disk swapping, you might want to look at Affa. The process will be fully automated, and will better handle disk swapping on an irregular schedule.
Your choice.