White Spa Skimmer Liddeck cover-6 Inch-(White)-by Aqualine

What is the diameter of the center hole? I need this for the auto refill but it sets into the bottom so I need the center hole to be 1".

does this lid have a notch on the bottom side?

Is there an inner rim underneath to keep it centered on the hole and what are the dimensions? My hole is 5.5”

Is there a 6.5 inches lid?