The color print viewing filter set is a "nice to have" item, I'd say darned near indispensable if you want to get the colors on your prints right. I'm not sure about the cibachrome filter sets. They may or may not have the proper amounts of filtration necessary for your set up. For printing from C-41 negatives onto RA-4 paper, you will likely not need the cyan filters at all. See what you have there and compare it to the filter pack starting point recommended by the paper manufacturer. Kodak publishes very comprehensive documentation about cc filters and color printing. See this example. Fuji is less clear about the subject, or at least makes the information a little harder to find.