That's an option, but the big question is about "where it means sht".
Considering we're talking about constructed languages, whether "it's supposed to read `sh`" or "it's supposed to read `sht`" is defined by the author of the language.
On top of that, even coming to a conclusion on what it's supposed to read like means extrapolating it from present-day languages or from the now-dead languages. In a lot of cases, different languages will just have different readings. I.e. consider these words:
Plus there's the weird separate word [BG "sht" щателен - RU "tshch" тщательный].
Barring the loaned words from mostly Germanic origin, it looks like one language just sticks to "sht", while the other prefers "shch" and considers the "t" redundant. The interesting exception is the "що - что" pair, which is seems to preserve the T sound.
Considering we're talking about constructed languages, whether "it's supposed to read `sh`" or "it's supposed to read `sht`" is defined by the author of the language.
On top of that, even coming to a conclusion on what it's supposed to read like means extrapolating it from present-day languages or from the now-dead languages. In a lot of cases, different languages will just have different readings. I.e. consider these words:
Group 1 - BG reads sht, RU reads shch
BG щипя - RU щипаю BG щастие - RU счастье BG ущърб - RU ущерб BG щит - RU щит BG вещ - RU вещь
Group 2 - BG reads sht, RU reads sht
BG нещо - RU нечто (Russian reads as "cht" here, but close enough) BG що - RU что (Russian reads "shto", at least in modern reading)
Group 3 - loaned words mostly try to mimic original
BG щора - RU штора BG поща - RU почта BG щанга - RU штанга
Plus there's the weird separate word [BG "sht" щателен - RU "tshch" тщательный].
Barring the loaned words from mostly Germanic origin, it looks like one language just sticks to "sht", while the other prefers "shch" and considers the "t" redundant. The interesting exception is the "що - что" pair, which is seems to preserve the T sound.