I may order some of this and give it a try, looks like you would want around 1 or 2 percent for the rub. Looks like a 1 lb is around $17.00.
http://www.americanspice.com/silicon-dioxide/Product Description
Silicon Dioxide Powder is vital because its porous structure allows it to absorb moisture and prevent clumping and binding of ingredients, with which it is combined. From flour for baking and cereal mixes to home-made seasoning and spice blends, Silicon Dioxide is a “magic powder” that can improve the quality of all your projects. Why search any further for this hard-to-find item? Our customers agree that American Spice Company can deliver exactly what you need with the best customer service. Stock up on Silicon Dioxide today.
Usage:
Used as an anti-caking agent. When using Silicon Dioxide, add less than 2% by weight.
Ingredients:
Silicon Dioxide
Silicon Dioxide Safety
Silica is not digested or absorbed in the intestinal tract, which means it poses no risk of toxicity. Silicon dioxide is "generally recognized as safe" -- or GRAS -- by the U.S. Food and Drug Administration. Although kidney stones may form with consumption of massive amounts of silica over a long period, the amount of silica in food, pharmaceuticals and supplements is not significant enough to cause stone formation or other side effects.