Well I only use Harmonic mixing when I have some songs left in my playlist, but I really don’t know where to fit them in. But I must say that most of my “best-mixing-combo’s” exist out of songs that aren’t even close in the Harmonic Wheel. Just keep practising and most of the time you will hear songs that will fit together 😉
(For example: I recently discovered BjornBerg, he sounds a bit like Avicii, so I most of the time mix him up with that)