While sculpting the sun face, there was very little effort made to make the model conform to a particular size. However, this is an important consideration when building the model for 3D printing because of tolerance considerations, which will be covered in more detail later.
Every 3D printer has a range of print areas that it can handle. Naturally, if designing for a particular 3D printer, this should be taken into account.
For this project, the model is going to be sized so that it will be too big for any printer to print. The smallest popular 3D printer on the market has a print bed of 120 mm squared, or about 4" on each side, so that one will be what this model will be resized for.