After you've made your changes, start a "New from Scratch" drawing to check whether the changes went through. If all is okay, shut down TurboCAD and go to the "Built-In" folder (%AppData%\IMSIDesign\TurboCAD 2018\Professional x64\Data\Profiles\Built-In). Copy the file "tcw25_xml.ini", go up to the "Profiles" folder (Alt+Up Arrow) and paste the copy there. If you need to dump the contents of the Built-In folder later on (due to some corruption), you have this copy to get things back to normal. This only affects New from Scratch, not existing files or Templates.
Stupid cheap Forum software won't allow me to post the two paragraphs in one post.
Designer, Deluxe, (Basic, Expert, Professional), Platinum
Windows 10 Pro (1909), 64-bit