After installing these originally… we had a slight problem.  80% of the plates came from an old installation we did at a restaurant.  The Picture Brackets were attached to the back of the plates with Liquid Nails… they are still holding on strong!!  The new plates I added to the mix (mostly a few of the outermost row) had the same Sawtooth Picture Brackets glued to the back with the same glue… But they have all fallen off.  I did let them cure for about two weeks prior to installing them, so needless to say I was annoyed.  This was one of my absolute favorite elements in our new yard, so I had to find a way to keep them up.
Problem solved…. albit a time consuming option.  Screws! I used Glass & Tile Drill Bits, and patiently drilled holes in each of the new plates.  Directly in the center of the plate.  When using these Drill Bits, you have to let the Drill work for you, you have to apply a little pressure, but not too much as the plates will crack in half.  Fortunately, this only happened once, & I had a back up.  
I say the process is time consuming… it doesn’t take that long, but it does take anywhere from 2-5 minutes to drill through each of the plates.  But once they are completed, you simply screw them into the wall (not too tight of course).  And they will not be coming down this time!
Plus, after further research… this is how Kelly Wearstler’s Wall was installed at the Viceroy.  So if it is good enough for KW it is definitely good enough for me.