Full Backup and Restore to a different device

I've spent literally hours days trying to find a solution to my problem here so thought I'd ask you guys! You've been good in the past!

I have had an app developed which I am preloading onto Samsung Note 10.1's before onselling them directly to my customers. I need a quicker, and less error-prone way of setting these tablets up before sale.

In general, up until now I have been

  1. Turning tablet on
  2. Get past all the initial login screens, dropbox, samsung update, google account etc
  3. Change about 10 settings (sound, display, lockscreen etc)
  4. Delete all the default homescreens and set a new wallpaper
  5. Install approx 4 applications

I have the potential to need to setup 150 tablets or more in the coming month, and they all need to be Exactly the same, so I've been looking for a way to speed things up. Initially tried root > nandroid backup > restore via recovery (not ideal) - then tried some backup apps Titanium, Settings backup etc which didn't seem to work (root required for most)

The latest method I tried was an Android Backup over adb. This seemed to have the most potential, got a full backup etc, but after restoring to my first 'clone' tablet, it got stuck in a bootloop.

Does anyone have any clues as to what would work best here? I'd really appreciate some good old Verge help!