The rack deadlift is great for lifters with less range of motion, but can also be used to work the top range of the deadlift with a heavier load.
Typically, the rack deadlift is set up with the bar just below the knees, but just above the knee is fine too. If you don't have a rack, use a few 45 pound Olympic plates to elevate the bar into position.
Sometimes it's really interesting to dig into the microscopic details of training and nutrition, to dissect the body of academia and examine every little study. That's how we learn things. That's how we refine the science that later helps us get bigger and stronger and leaner.