Customized version of https://www.thingiverse.com/thing:13511

Created with Customizer! https://www.thingiverse.com/apps/customizer/run?thing_id=13511

Using the following options:

globalThickness = 1.2
shelfLength = 120
shelfWidth = 20
backingheight = 30
numberOfHoles = 6
holeDiameter = 4
holeLargestDia = 5
holeSmallestDia = 2.5
triangleGussetWidth = 20
progressiveHoleSize = 0
triangularGussets = 1
useToolGuides = 1
guideCrossSupportHeight = 7