So I can add new templates for single files, but I want Xcode to uses these files when setting up the new project (most noticeably the Controller and Delegate .h and .m files). How do I do that?
In addition to the templates for individual classes that you found, there are also templates for the various project types. If you just want to replace a single class file that is already being added in the projects you can just replace the file in each of the project template files (as long as the names are the same). You will need to copy the template files into each project template that you want to change it in. The other option is to make your own project templates with whatever default files you want.
来源：https://stackoverflow.com/questions/2708164/xcode-change-project-templates