“cz” marks the same sound as the English “ch”. “j” marks the same as “y” in “yes”. Otherwise you read it letter by letter, a bit as if it was Spanish.

So… Is Ch’yvinos’tavch legible enough? :) Although, the pronounciation of the j would be so weak that you could perhaps skip it. It does alter the sound a bit, but doesn’t really sound as an independent sound in this word. So, also Ch’vinos’tavch could maybe be a valid transcription? And of course real Polish language does not have the combination czj anyway :)