Stacked leverage puts both the pin and the cg or mb 3 3/8" from the PAP. This maximizes the flare, whether it's the strongest layout or not depends on the bowler, condition, etc.
Pin in and pin out refers to the distance between the pin and the cg on an undrilled ball. Less than 1" is pin in, over 1" is pin out.
Pin up and pin down refers to the height of the pin above the midline of the layout. In general if this height puts the pin below the finger holes, it's pin down. Above the finger holes is pin up.