can I schedule photo library syncing to use off-peak data?

When iCloud Photo Library syncs from my Mac it uploads many gigs of data, which the first time it did so put me over my monthly data transfer allowance, so had to buy additional temporary data from my ISP for that month or suffer shaped bandwidth back to slow modem speed. My Internet plan allows 20GB peak (8am-2am) and 20GB off-peak (2am-8am) per month. Is it possible to use Automator to schedule the next Photo Library syncing for, say 5am, so that it uses my off-peak data allowance?

iMac 27-inch, late 2009, 2.66GHz Intel Core i5, 4GB RAM.

OS X Yosemite 10.10.3. Photos for Mac 1.0.

Internet connection is NBN Fibre to the home with iiNet Australia, 50Mbps down, 20Mbps up.