Depends on the person, just do what's comfortable.
Come on, you can do better than

The heavier you go,
the bigger the stress on a wrong place. You're familiar with these kind of calculations of lifting techniques?;

Your core is the weakest part of your body, it becomes the restricting factor,
look to excersises like deadlift and squat, you start using a belt to keep everything intact. For BOR, you can go really heavy with an smaller angle,
or you can go very deep using a bench, with this technique you eliminate the influence of your lower back, and you can't cheat with the last reps.