Try this:
-> OffScreenMouse: Set position to (lerp(SmallScreen2.BBoxRight, SmallScreen2.BBoxLeft, unlerp(SmallScreen.BBoxTop, SmallScreen.BBoxBottom, LayerToLayerY(OnscreenMouse.LayerName, SmallScreen.LayerName, OnscreenMouse.X, OnscreenMouse.Y))), lerp(SmallScreen2.BBoxTop, SmallScreen2.BBoxBottom, unlerp(SmallScreen.BBoxLeft, SmallScreen.BBoxRight, LayerToLayerX(OnscreenMouse.LayerName, SmallScreen.LayerName, OnscreenMouse.X, OnscreenMouse.Y))))
{"is-c3-clipboard-data":true,"type":"actions","items":[{"id":"set-position","objectClass":"OffScreenMouse","parameters":{"x":"lerp(SmallScreen2.BBoxRight, SmallScreen2.BBoxLeft, unlerp(SmallScreen.BBoxTop, SmallScreen.BBoxBottom, LayerToLayerY(OnscreenMouse.LayerName, SmallScreen.LayerName, OnscreenMouse.X, OnscreenMouse.Y)))","y":"lerp(SmallScreen2.BBoxTop, SmallScreen2.BBoxBottom, unlerp(SmallScreen.BBoxLeft, SmallScreen.BBoxRight, LayerToLayerX(OnscreenMouse.LayerName, SmallScreen.LayerName, OnscreenMouse.X, OnscreenMouse.Y)))"}}]}