When I used it, I used just a tiny bit over FSG--I'm talking less than dime sized, probably. I'd put it in my palms, rub my hands together and then scrunch it throughout my head.
I tried mixing it in with my leave in (Tresemme) too, and that worked pretty well; for some reason I preferred it over the FSG by itself. Alas, I can no longer use it, as it makes me break out
I am a sad, sad panda about it too, because I really liked it!