The acceleration of an object rolled down an incline does not depend on its size. For an object on an inclined plane,

$$a=g\sin(\theta)$$

where \(a\) is the acceleration, \(g\) is the acceleration due to gravity \((g=9.8\ m/s^2)\), and \(\theta\) is the angle of the incline. As you can see, the acceleration does not depend on the mass of the object, so a smaller object will accelerate at the same rate as a larger object down the same incline.