How wide of tires can you fit on your 700c bike? Do you have fenders on it? I wouldn't bother putting studded tires on a bike without fenders on it. I would hate to ride without fenders in conditions where I wanted the studs.
I have run as narrow as 35mm studded tires, and I like them. I'm now running 50mm studded tires, and I like them even more, but they also have four rows of studs instead of just two.