The analysis forgets the very first problem after someone is killing criminals visibly: Light relies on TV to find them. You could tell it's Japan without doing any math about time zones or anythING, as TV itself brings in the bias. To pretend you are elsewhere, you have to be consuming foreign news to even begin to have a chance to hide yourself
Have you seen the show/read the manga? That's precisely the first tactic L uses against Light - he broadcasts that he has precise knowledge that he's somewhere in the Kanto region of Japan based on this timing. It's also mentioned in the article which you claim forgets to cover this.
to be more precise, OP says L should use the fact that Light selects criminals only when they appear on Japanese TV.
In the manga, L did track down earliest of murders to Japan and therefore started his "world" broadcast from one region in Japan.
Light got angry at broadcast's message.and lost his cool, and fell into the trap of "world broadcast"