Scheduling SD! backups on NAS doesn't work?

[Dogen]

I guess I have two questions.

1. I recently set up a NAS and it came with a free goft - a 500Gb drive. Previously Time Machine and SD! had been sharing a 500Gb drive, and since I'd read that getting TM to backup to a network drive was dicey, I decided to copy my SD! image to the network drive and schedule it to backup there. Upon first copying it, I performed a manual backup to test that it worked and it went off without a hitch, so I scheduled a backup for that night and left it alone. The next morning I checked and the backup hadn't run - the last modified date/time were when I did the manual backup. I rescheduled for that evening, same thing - nothing happened. I did another manual backup, again, no problem. Weird. Any thoughts on why I can't get scheduled backups to perform on a NAS, even when manuals do?

2. My SD! image is 174Gb, even though the source drive only has about 70Gb of data on it. I use "Backup - All files" paired with Smart Update. I was under the assumption that my SD! image should be closer to the size of my source? Is that wrong?

Thanks for any help you might have with either question. I'm really pleased with SD! generally - I'm new to Macs, and have only had it running for six months or so. It's been great to have.

Thanks!