When you said Leg Sled, I was thinking of the sled where you stack weight on top then push it across the floor.
And as Carleton said, you should be able to press a lot more weight than you can squat or deadlift.
Lastly, I prefer going barefoot as the weight gets heavier. I am much more stable without shoes. And I have incredibly wide feet, so I can't really find lifting shoes that fit me well.