This is a remix of the excellent bit trays by swholmstead .I didn't do anything except extend and taper the base to cut down on print time and filament use. They still stack exactly the same way as the original but because of the scaling issues when importing, they're slightly smaller than the original "large" trays. My problem with the original was that the bottom of the trays ended up being very rough feeling, like sandpaper (but that might just be my printer)

Print with top layer and bottom layer set to 0, wall thickness 1.2mm. Zigzag infill at 20%.

About a 25% savings in print time and a 20% savings in filament.