Can I ask what are the power plugs that you use to power the 12V and 5V distribution blocks? Do you have a link? Or are they just DC adapters that you cut the plug off of and wired to the blocks?
The power adapters are simply 12v 2.5a and 5v 3.0a DC which you can find on Amazon. Cut to size and wire in.
I am a reseller and I too have placed 8-9 tablets on the wall which was locked with Scalefusion kiosk mode for displaying certain ads for our visitors.