First, with regards to Oil Dry, Grog seems to state what I have found. I used a product that is sold through my local auto parts store (can't remember their exact name - but can get it if anyone really cares) for two years. I found that it broke down and left the sludge at the bottom of the pot, but after two years it was still relatively stable. More so than akadama. I did an expiriment and put some in a jar of water for 1 year, shaking it every month or so. It left a nice layer of silt at the bottom of the jar, but the individual granules were still the same consistency - some resistance when squeezed. So, for those that use oil dry products - test and use with caution.
With regards to Miracle Grow and Oil Dry Mix Dwight, well, it is a bad mix but everybody here has used their share of bad mixes. Don't sweat it too much. Go with what Tom recommended and you'll be safe. In your neck of the woods, error on the side of moisture retention - and hope you don't get 19 inches of rain like your neighbors.
As for this Shimp, well... Wasn't there a bunch of hub-bub about this tree on another site last year? Where did it come from? What root work was done? What wiring? What foliage? I suspect that this tree might be suffering from a variety of issues and it might be difficult to narrow it down to soil or sun or wiring or whatever.
Don't sweat it. It is part of the learning process...