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.
The author claims that the concepts are platform-independent and that they give examples for Linux when needed. I don't know enough about the topic to know if that's sufficient.
[0] https://github.com/intel/haxm