i collected from an asphalt shingle roof that had to be 10 years old and their was always an oil sheen on top, wasn't much (that i could see), but it bothered me for sure.
i'm not sure about which strains, i know some help, but i have heard a bit about ingesting small amounts (1/2 g) of mushrooms giving people relief from migraines for 2-3 months. sorry i couldn't be of more help.
i use infused butter for my dogs anxiety and arthritis. they only need a very small amount to help them, don't over do it, although it's trial n error on dosage. good luck!