The number of perimeters also called shells will determine how thick the hole wall is. Also for something small like that you can print it with high infill rates so there is lots of meat.
However, most door bell buttons are screwed to the surface with 2 screws or they are mounted with mounting tape. Why not build your riser to match the button and just get longer screws that pass through the block and into the surface.. Or use mounting tape for riser to wall and button to riser. You are in control of the entire process so experiment and find out what works, that is the beauty of fast prototyping with a 3d printer.