¾ teaspoon of xanthan gum per cup of flour & one teaspoon of methylcellulose per cup of flour. Clear Gel in place of methylcellulose has the advantage of being much cheaper and more readily available than methylcellulose.
2 parts white rice flour
2/3 part potato starch flour
1/3 part tapioca flour and a teaspoon of xanthan gum
Beware of spices which contain wheat flour! Many manufacturers use wheat flour to keep spices from clumping.