Problems with Apple Configurator

I've been having trouble with Apple Configurator lately. For reference, the devices are not being supervised. They are just being restored from a backup file with four profiles, and two free applications. The backup file is fairly large - coming in at 12.9GB. Using a Mac Mini with around 150GB of free HD space. I'm using a Bretford tray so I usually try to plug in 10 devices at once. This has worked in the past and have only recently run into problems since the update to Configurator 1.4.2 and/or iOS7. So, I'm able to to run Configurator with 10 devices plugged in (I've since started only plugging in 6) and no matter what I try I cannot get more than 4 devices to successfully complete. And actually about half the time less than 4 actually complete successfully. The error I'm getting is Code 4 and the description just says "unable to restore backup." It takes about an 45 minutes to complete one device and about double that to complete 10. So getting 10 done at once is a huge time saver. When I'm only getting 4 devices completed and many time less than that at almost an hour, it is absolutely maddening. I've tried every combination of restarting and reinstalling Apple Config and still the problem exists.

I have a constant stockpile of iPads, Minis, and iTouches coming in so it would be extremely greatful if anyone had any tips or advice.

Additional questions regaurding Apple Config.

1. Is there any way to install multiple profiles on multiple devices on the newest version (1.4.2)? It seems like the new version only allows you to install 1 profile on multiple devices or multiple profiles on 1 device.

2. Everytime a backup fails, Apple Config saves that backup in the MobileSync folder buried in the Containers folder. Each of there backups is almost 13GBs, so I'm having to constantly delete them to conserve HD space inorder to run so many devices at the same time. Is there anyway to prevent this from happening or auto delete failed backup restores?

I know this is very long winded but I wanted to get as much on my info out there as I could. Anyway, thanks for any help that anyone can provide!