Not all mine, but have been involved with 6 6" pads (all for 8,000 bushel bins or smaller) and a dryer pad... we used hog panels in each one of them up on 2" chairs and have had zero problems with any of them, some up to 10 years old now.  Not a lot of weight in any one spot, but I would consider panel in something a little larger.  No, it's probably not "industry standard" but how many of us have everything 100% "industry standard"?  Some folks probably have a larger budget than I work with on projects though.  For what it's worth, tearing down a bin and moving it first of the year that was set in '77, 6,000 bushel 21 footer, set on a poured 5" slab with zero reinforcment.  Been almost 40 years and just recently started giving trouble.  A little reinforcement would have gone a long way obviously.