Spades had a great point that I actually used myself. Because I only harvested 2 little sisters throughout my play through on Hard I had next to no new slots for what the guide calls for. Using the dummy helped immensely when reloading and just playing through overall.
Be aware those that haven't beaten it yet, when you drain Atlas for the final time splicers can still kill you. I found this out the hard way as I was in the middle of draining him but had less than 1/3 of my life left. Needless to say I made sure the next time I drained him for the final time I was full of life.