Looks handy to me. A couple of minor comments: 1) Why do you show a dialog informing the user that the file will be created from the template? This information could be moved to the previous dialog saving one click. 2) From my distant memories of MacOS 8, file extensions are not encouraged on MacOS. Perhaps someone who still uses MacOS could comment on whether this seems sane on MacOS.
-- John C. McCabe-Dansted