how far it zooms out is the third value in the clamp(currentLayoutScale,minLayoutScale,maxLayoutScale)
set the max value to something lower, like 1 for default for example.
to reset the camera to the center of the layout when zoomed out you could do something like this:
if layoutScale = maxLayoutScale set camera postion or scroll to
x: lerp(self.x,layout.width/2,speedYouWant*dt)
y: lerp(self.y,layout.height/2,speedYouWant*dt)