Interesting. I remember playing with VT-x using Intel's HAXM framework [0] that installs its own Windows driver with a much nicer user-facing API, basically does what the chapters 2, 3 and 4 of the tutorial end up implementing, so you can spin up an empty, ready to go VM already in the 64-bit mode quite easily.
[0] https://github.com/intel/haxm