 
I used 5 1/2 x 1 inch composite deckboard for the tray.  STL is for the legs only. 
Sliced with Cura and set initial layer horizontal expansion to -1mm to ensure the board would fit in the hole.  You may need to adjust the sizing a bit to fit your board. 
Distributed under the Creative Commons Attribution 4.0 International License (CC BY 4.0).
December 3, 2020