Poor Man's Radiant Barrier (Update)

I posted a few weeks ago about ordering a case of emergency blankets.  Well I received them and took advantage of a relative lull in the summer temps to staple some in the attic.  You can see from the pictures that I did my best to lay the sheets out on top of the insulation.  I used a staple gun to tack them down, but I'm afraid they are prone to tearing.  I'm curious to see if they stay in place after a monsoon, or simply end up crumpled into a ball in a corner of the attic.  I'll never really know how effective they are because I can't physically reach most of my attic space.  These photos show about 5 blankets out of maybe 7 that I installed.  It would probably take 30 or 40 to cover the whole attic.  I'm also using these sheets in a few windows to keep the heat out.  They only cost about $1 each when purchased in bulk from Amazon, so if you think you could use a radiant barrier somewhere, you can't beat these for value.