The finished board is incredibly stiff and sturdy without feeling heavy. I used 25% infill but probably could have gotten by with 20% or less.

I used 3 different pieces of 1.5" x .75" wood I found on the 'value wood' shelf at Menards. The actual width & height of each piece varied slightly (and thus the model's wood slot sizes vary slightly) but as long as the pieces you use are the same width and height (or smaller) than the dimensions below they should work fine.

The length of A, B, and C can be whatever you need them to be. Each piece of wood will fit in a slot that is 20mm (25/32") deep - so be sure to add a total of 40mm on each side.

To test if your lengths will work: if you add together the lengths of B and C and then subtract 20mm, they should equal the length of A.

Example: (160 + 210) - 20 = 350

Dimensions of the wood I used (in millimeters):

Print settings I used on Prusa Mk4:

Material: PLA

Preset: .20mm (Speed)

Supports: Everywhere

Infill: 25% (20% would probably be fine)

When slicing it's a bit tricky to get the left and middle pieces to fit within the printable area. There is less than 1mm of wiggle room but it can be done.

I ran out of white filament while printing the left piece which is why it is suddenly blue on one side