Hm, you can only use till in the combination en (or similar) … till, which means you cannot use it with uncountable nouns. So if you want more salt, you need to say mer salt. Or like en tesked salt till 'one more teaspoon of salt', where the salt is still uncountable, but the teaspoon of course is countable.
Looking at the Svenskordbok app and running it through Google translate, that seems to be about right except duk is more specific than en bit tyg and has specific types of pieces listed; a decorative cloth for table or chest, oilcloth, an art canvas, a projection screen. Mods?
duk and tyg seem to come from the same Germanic root, cognate with German Tuch and related to English word for a type of plain tightly woven fabric, duck.