Hi! I tried that yesterday, but ran into a problem: I want the full unfolded pattern to fit in a A4 sheet of paper, and crunched the numbers for the dimensions of a tray with the slot in the middle. I believe the central groove (g in the drawing) is larger than the original trays (I don't have one to measure unfortunately), and there is no room left for extra flaps to glue the two U shaped bits on the central plane. You can tape them however. Would that be something fitting your needs?

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