“While I don't claim to be a qualified plumber, I understand engineering principles, and one would assume that for the Wirquin trap to have a reasonable change of sealing, the area in the shower tray adjacent to the cut drain hole, would need to have reasonably consistent thickness. Mine varies from 12.5 to 6.9mm, due the rough finish on the underside. This is expecting a lot for a 6mm thick rubber gasket to take up.
Of course, with sealant liberally applied to the hard inner washer, and lots of glue on the rubber, maybe it will seal, ... maybe it won't.
One things for sure, the trap won't pull up evenly on the three screws with a thickness variation like that.
My plumber said buy from "Just Trays", but I went for the savings, and am now paying the price !”
