I used one, 4x4 sheet of 0.8mm ply for the rib gussets. I cut the sheet into 32, 6" x 12" pieces. I drilled a few 1/16" holes in a stack of 28 layers of 6x12 and glued round toothpicks through the stack to hold everything together. I used my bandsaw to cut stack into two, 3" x 12" stacks. I glued IronDesigns gusset patterns on each 3 x 12 stack, after adding a few extra gussets to the drawings. I then sawed all the gussets in each 3 x 12 stack at one time. I did have to sand the edges of some gussets that were a little rough. Edit: Found notes that said I had to get more 0.8mm ply to do K-block gussets. Bought 2x4 sheet, had lots left over for other things.