Bill, I'm glad you're happy with the way the sand is working in the hoppers. I would offer a word of caution from personal experience maintaining full size equipment operating in and around sand.
Sand will readily stick to exposed grease and oil. Sand with static cling could be especially problematic. When grease/oil is in place to lubricate gears and moving parts, the grease/oil becomes an abrasive paste, greatly reducing the useful life of those parts.