For all the strong opinions and somewhat positive self image Bird's has, I do think that if nothing else, he knows his body well enough to make his own calls on what works for him. We all respond differently to different training methods. Find what works for you and go with that.
As for the back rounding stuff, I won't enter into that convo, if I can't squat and DL anything remotely deent without busting myself in half, I have no place lecturing others