On mix powders: I've been struggling a bit with the whole "cooking whole spices" thing. Again there are conflicting opinions. Cook : Don't Cook. Cook Together : Cook Separately, Cook Powders as well : Don't cook powders, Grind in M&P : Use Coffee Grinder.
One thing I've troubled with is how long to cook spices, whole, big and small. There is a big difference between a Cumin Seed and a Black Cardamom or a huge chunk of Cassia Bark.
Looking at something else, I came across a recipe for an authentic "North Indian Curry Powder Mix", which looks pretty good too by the way. What struck me as "Wow, look at that!" is the instruction of cooking the whole spices.
"1. Place all ingredients, except last three, in a karahi or wok or griddle and dry roast for 10-12 minutes.
2. Cool.
3. Grind to a powder."
This includes Cumin Seed, Black and Green Cardamoms, Bay Leaf and Cinnamon Sticks among other things. The "last three" mentioned by the way, are powders, so at least that is answered for me.
Here was me worried about it. 10 - 12 minutes. I think I'd have a bush fire by then.
Other noteworthy things from the same source are that the basic Garam Masala spices are not roasted at all in order to preserve the essential oils and aromatics, where as the Kashmiri GM is roasted but only for 6-8 minutes.