A high wall thickness of 5 shells/perimiters will ensure solid snap connectors. From there settings can vary based on your desired outcome. Print solid for the most robust and long lasting joints, or print a lower infill with 0 top and bottom layer thickness for a cool exposed infill pattern.
This download contains many variations, including two part versions for printing with dual extruders or multiple processes. Combine the "_Edge.stl" and one of the "_Inner.stl" files.
Visit the Intro to Polypanels site to learn more.