Regarding Git and Orbiter migration:
When using SVN I have usually just 'Checkout' a copy from the SVN repo on a top of an existing Orbiter installation but it looks like the Git can't do that, it needs to do a 'clone' in an empty folder. So, I studied a bit of the CMake and added a cmake-files to the project. So, you can create VS Solution and Project files from there for your preferred VS version. Running the CMake will automatically copy necessary files to your Orbiter Installation Folder. And, So-far, it appears to work reasonably well.
I have also change the directory structure to match the one used by the Orbiter. So, the source files are located in /Src/D3D9Client/ and the sample projects are in the old place /Orbitersdk/samples/