You can kill about 115 to 125 cave horrors in an hour without a cannon. Killing them without a cannon is going to be the best way to go for a profit. A large amount of your profit is going to come from the black mask that they drop.  If you go there with very high-level equipment and a cannon, you can kill over 300 an hour. You will not make a lot of money this way, but you could get a black mask in less than two hours on average if that is your goal.  If you want to hear an exact number, you can count on a profit of 200 to 500k an hour depending on your gear, concentration, and luck.