The amount of Ketores required was the amount that could fill the hands of the particular Kohain Gadol who performed the Avodah. This included the palms and fingers when they were cupped together. According to some opinions, the Kaf (spoon) into which the Ketores was placed was selected to match the size of the individual Kohain Gadol's handfull. Tosfos contend that the Kaf must be larger, for if not, some Ketores would inevitably be lost when he later pours it from his hands back into the Kaf.
