But with White's history of running 1 gap, being heads up requires the OL to protect every gap, because they don't know wher the DL is going and if a LB is coming thru the opposite gap. So it also allows for more 1 on 1 match ups for the defense.depends on what you're trying to accomplish on D. Gap alignments are typically shades and require a DT thus getting a two for 1 freeing up LB's to make plays. Stack alignments can be feast or famine depending on what your doing with them.