This is how I make tallow - except I don't have a food processor - so I just used the kitchen scissors to cut the fat as small as I could stand to cut it (hand pain) and just went from there.
We're using it the same way most people use lard, mostly frying or for additional oil for things right now. I finished it, and it fills 1 mason jar - so about 2 cups of tallow from that big ol' bag we got.
ETA: We aren't like frying fries or anything - just like bits of meat or whatever needs a tbs or so at a time.