It depends on the type of fermentation you get: if it is vigorous, you'll likely have a higher temperature inside the fermentation vessel than if you have a beer that chugs along for 2 weeks. With S-04, a lot of people have success fermenting in the lower range. I would put my fridge at 60F and forget about it, only increasing the temperature by a degree or two if the fermentation seems sluggish.
I'm using S-04 in a stout right now and it went gangbuster at 60F ambient temp in a swamp cooler. You'll like S04, it smells absolutely amazing when it is fermenting.