A stacked layout is any layout with the pin to PAP and mb (or cg) to PAP distances the same, so the reaction will depend on the distance used. If you're referring specifically to stacked leverage layouts (both distances 3 3/8"), you will get maximum flare. How this will react will depend on lane conditions and how you throw the ball. On oily lanes most will get a fairly good reaction, if the heads are scorched it will burn out by the time it reaches the end of the pattern. -- JohnP