[DCP-o-matic] DCPomatic

Hi Carl, I am using the DCP-omatic to convert my film for a festival. I'm having a bit of trouble and hope you can help me. It was shot in 30fps, but the programs says that is an unusual frame rate. Should I change it to 24, and if so, do I just change it under the DCP tab? I want to make sure the video quality won't be compromised. But it sounds like it's okay to leave it at 30, from what I've heard. The program is also advising that I create an SMPTE DCP instead of an interop, because of the frame-rate. What is the difference? Should I do that? Also, under the DCP tab, I set the container to 16:9, but the program is saying if possible to put it in scope or flat, but those aren't the right size of my film, and leave those black edges on the sides of the picture. Please help me if you could. I've been working on this for a few days, and have to complete it soon for it to show in the festival. Thank you! Josh