You can use the Lyric Diphonizer plugin for that. Drag and drop the folder into the plugins folder, open the ust you want to use, select the notes you want to convert, and then press N on your keyboard to bring up the plugin list.
It also depends on how people work. I personally create an base/untuned version of an ust and then make a copy and tune that, but I know a lot of people just import a midi and start working.