The bench press is principly a tricep excercise or should be when preformed correctly (assuming the goal is to lift as much as possible). I am not surprised at all that focusing on your triceps produced good results. In general, it would be my expectation that the most efficient way to move your bench numbers is to strengthen your tris.
I personally am not a big fan of supplemental work. To my mind, the best way to build a big bench is to spend some serious time on the bench preforming your usual benching, some JM presses, board presses (to address sticking points), ect.
Predominately, I feel the same about the other lifts as well in that there are excellent variations similiar to the actual lift that can get you through the point at which you miss that particular lift. Addressing weak point in this way has the added advantage of helping you groove a useful and more efficient muscle recruitment pattern which is essential to building a stronger lift.