How much brown sugar for priming

I've got a British Best Bitter I'm about to bottle tomorrow and the recipe calls for 1/2 cup brown sugar for priming, however the kit kit also came with the usual corn sugar. Should I follow the recipe and use the brown sugar, or just go with the corn sugar? I'm a little concerned with the amount of brown sugar called for, 1/2 cup doesn't seem that much. How much should I use if I go the brown sugar route?

No idea about how much, but use brown sugar. Go the unusual route.