Ihor, given a choice, I would vote for the second (using @) but would be happy with either. My needs are simple, however, so whatever is easiest to implement would be fine with me. I'm not bothered, for instance, about the daylight savings transition as I'm usually in bed... ;-)
But I definitely would love to have time zones of some sort as I'm frequently travelling between different zones and having meetings across zones. Thank you in advance! eric -- : Eric S Fraga, with org release_9.6.1-199-g7ad779 in Emacs 30.0.50