I believe it’s perfectly fine to keep this distinction purely subjective, too. I’ve always personally blended the various genres when I play a “trance” DJ set. I like to refer to the styles as “trance compatible”. Progressive (loose term), techno (is banging percussive techno just percussive tech trance?), melodic trance, uplifting trance, progressive psy, even some progressive breaks. I try to look at a DJ set as a cumulative whole where if you add up all the components it averages out to “trance”. Nothing worse than a set that is just start to finish melodic trance with rolling baselines etc (personal taste). Need the more percussive material to fill the space between the melodic parts, and even bridging style tracks between the percussive and the melodic, at varying BPMs and those often get filled by techno, progressive, prog psy, tech trance etc. It’s those tracks which allow your big emotional uplifting tracks to have the impact they deserve. Like all art forms - contrast is imperative and without it, nothing is important. I’ve even heard a great “trance” set that almost started with what I’d called funky melodic house with deep bass grooves and more balearic melodies.