PLA Choose a quality 0.15 mm layer height profile (or equivalent) and turn adaptive layers on with layer height in the 0.1-0.2 mm range. Use 3 perimeters with a sparse infill (10%). Bridge settings should be on, as some pieces have bridges. The longest bridge spans 10 mm. A brim will ensure all corners stay on the print bed. If using a Slic3r variant, you will have to do the following trick to get the overhang of piece1.stl to print perfectly: untick the "Ensure vertical shell thickness" option (visible under Advanced settings), add a box modifier encompassing the overhang area, and set the number of top and bottom layers for the modifier to 0. Otherwise the overhang surface will be rough. This is probably related to this issue: https://github.com/prusa3d/PrusaSlicer/issues/1054 https://github.com/supermerill/SuperSlicer/issues/253 The project files included have the print settings and trick described above.