Spell GLK in Russian language without any use of Latin letters, as if you were Greek or ancient Greek, and make sure to make your text easily readable by any reader. Make sure to deliver meaning, rather than transliteration.

Your absolute goal is to take a product out of different culture and to make it natural in Russian empire. It should feel (the product name) as good, as it feels in that other culture. No transliteration is capable of such job. You *have* to be creative with the task. Use all your philological knowledge and experience. No ordinary solutions work for unordinary tasks.