DaVoice is right, you loose weight and rigidity. But you save material. It´s okay. I print nearly everything from PS with 2 outer Lines and 5% infill. Just try
You can rescale the files to 133.3 % to fit the 40mm size.
If you have an original Prusa printer I would suggest the slic3rPE-Edition from the Prusa Homepage. https://www.prusa3d.com/drivers/ . Settings for all prusa printers are included and automatically updating from the internet. For things from printablesceenery I use 2 shells and 5% infill at 0.2 mm layer height, it is enough. But I would suggest printing with cura. The settings are also to download from this page. The quality of the print is okay ( Slic3rPE is slightly better) and cura uses about 30% less filament in the out of the box settings. Only print parts which need support with slic3r, because of the better support in slic3r. For the first layer try 21mm print speed or lower in cura or slic3r. I do not use a brim, skirt is enough. The temperature is depending on your filament. I use PLA, it is cheeper then the others and provides good post printing abilities and it is paintable even without primer. Start trying temperatures between 210 and 215 degrees Celsius for the first layer and then between 205 and 210 degrees Celsius for the other layers.