It takes more for sure, but they make a ring that you can use to reduce the amout of coal for smaller cooks. Its just a round ring about 10" tall that hold the coal in a tighter circle. Do some research at www.eggheadforum.com.
I think you'll find the Large is the most versatile size. My next one will be an XL only because I have the other sizes. I use mine 3-4 times a week.