Hi zbuffer14,
Something you could try would be to delete the Engine/Intermediate folder after having built the Engine. The next time you open the Editor, it will take a little longer than usual as it rebuilds the parts of this folder that it needs. However, once that is done, you will have a much smaller folder and overall Engine size. Not quite the same size as the Binary Engine, but it will be significantly smaller than it was.
Keep in mind that if you do delete the Engine’s Intermediate folder, you will not be able to make any changes to the Engine’s source code and build the source code until you run GenerateProjectFiles.bat again. This will allow you to build the Engine again (which will require another full rebuild at this point), and then you can again remove the Intermediate folder to get the size back down a bit. In the case of your modified version of the Editor, you’ll want to make any source code changes before you delete the folder since it will be more time consuming to make changes to the source code after you delete it.
When I tried this myself, the Engine/Intermediate folder went from approximately 8 GB (after building the Engine) to approximately 9 MB (after deleting the Engine/Intermediate folder and then starting the Editor).