Re-paints work. To save space, you just need the following .bmp files from the desired re-paint;
Then, copy the texture.cfg file from one of the default Maule's texture folders into the desired Mentor re-paint's add-on folder and add to the aircraft.cfg as you normally would. You really only need the re-paint's "Carenado_mentor_interior3_T" file for the Navy 'B' model if you want something besides a yellow pilot helmet. For example, I added the Navy blue scheme by Kevin Jessee, and the default helmet is still yellow, unless you keep the Carenado_mentor_interior3_T from his re-paint in the navy blue texture folder.