>>7225637>Doing a negative BTN press with a squat weightThis is a fantastic idea and I can see no way that this could go wrong.
If you don't have a rack, you need to get your ass to a proper gym, or if you're determined to workout at home, stop half-assing it and buy a rack. In the mean time, you don't really need to do back squats. Front squats and pulls from the floor will be fine.