After you delete 7.4 and install 7.3 you may get an error when trying to open iTunes. Something about the library being from a new version of iTunes. Go to your iTunes folder (In your music folder>iTunes folder) and delete the file named “iTunes library.itl” and run iTunes again.
You will see you iTunes will be empty of music, podcasts, ect but they are still stored in the iTunes folder. In iTunes go to the "File" menu and then "Add folder to library". find the iTunes folder and then the folder for your music and it will import back to iTunes. Do the same for podcasts, movies, ect. The only thing you will have to do is subscribe to any podcasts by hitting the "subscribe" button again.