The paragraph above this post said to mount end slate screws last, so in confused a little. If you glue the seams do you need slate screws at all? Can the rails secure the slates without using any screws or do you still need the screws to hold the slates level? ThanksIf you superglue the seams of a 3 piece slate together correctly, you don't need to use the slate screws at the seams to hold them together! Think about it!!!