There is a 10mm x 10mm x 10mm cube hole and different sizes of square prisms. Before make a connector design you can test the parts how much fits with your printing settings and your 3d printer calibration.
In the simple design, numbers on the square prisms must be at the bottom before pushing them into cube hole. Because your bed heat and adhesion will give different sizes to bottom of the square prisms. But you can both test the heated and adhesioned surface and the numbered surface.
My favorite square prisms for the cube hole (with my settings and 3d printer calibration);
Heated and Adhesioned Surface: 9.2
Numbered Surface: 9.7 (If the last number must be even, i choose 9.6)
Filament Dünyası PLA