The instruction I have with my skimmer would suggest that working from the inside:
Front plate-Gasket-Liner-Metal wall-gasket.
What I do not understand is why would you place a gasket between the Front plate and the Liner. There could not be a leak there since they are both on the liner side. Does this gasket seal where the screw go?
It would make more sense to have the gasket between the liner and the metal wall.
Is the theory that the gasket will press the liner evenly against the metal wall and since the liner is soft the liner will seal itself to the wall. I could use three gaskets but I would need to glue the 1 extra gasket to the metal wall since it will not be accessible once the liner is installed