It's not difficult. Personally, I use dual layer discs for backups since, well, it's a backup. But in your case, do this...
1. MacTheRipper: if you want menus + movie, use FULL DISC EXTRACTION. If you want just the movie, using MAIN MOVIE EXTRACTION. Extract to a folder on desktop.
2. DVD2OneX: Choose the first option, MAKE FULL DISC COPY. It will ask where the VIDEO_TS folder is located, point it to the folder on the desktop you used for MacTheRipper. It will compress the movie (if needed) to fit a single layer DVD. Before it compresses, it will ask you whether to save as image file or burn. Choose BURN. DVD2OneX will burn the image for you after compressing. Very easy.
Any questions, feel free 🙂