Happy to help, I’ve received so much assistance from this forum that I’m glad to help with something myself.
It should go on the position parameter, not opacity, opacity can only take one value. Position needs 2 or 3.
x should equal the position that you want when the logos are visible, which if I understood is 56 pixels to one side of the position when there is no logo visible, so there’s a specific value that you need to enter there, disable the expression move your layer manually and check waths the value where it is.