I designed and made this display Superman Logo. I didn't like how larger prints would warp, so I separated the logo into 3 STL files, one for each color of the logo (red, blue, and yellow). One picture shows the logo files as they appear in CAD. Another shows the logo after I mounted the pieces to a stained and finished wood plaque. The default image shows the finished logo with the screws covered (I have included two files for your use as well - one cylindrical cover, another spherical). I will be making more logos as time goes by using these same techniques. I am very happy with the results.
I did not use rafts for any of the parts. It seemed to work just fine. For the blue outline of the logo, you will need to use supports, as there is a gap underneath that will cover up the other parts and hold them in place. If you don't use supports on this blue piece, the part will not print properly. Supports are not needed for the red piece, yellow piece, or either of the screw covers.
You may need to clean up the clearance holes for the screws. I used a Dremel tool on a low setting. Also, you will need to clean up the inside edges of the red "S" outline with an exacto knife or small tool. There is a small clearance between the red and yellow pieces, but may take some fooling with to get them to go together. But, when they go together, they stay nicely.
I used #6 wood screws (5/8" long) to mount the logo to the wood. The screws have a flat head. Either of the screw covers fit nicely over the flathead screws. You can choose cylindrical or spherical, which ever you like the best.