On Gittin 85b, Abaye discusses ways of carefully writing the get, so that an ambiguity cannot creep in which would indicate the opposite message. These include:
וְלוֹרְכֵיהּ לְוָיו ״דְּכַדּוּ״; דְּמַשְׁמַע ״וּכְדִי״. וְלָא לִיכְתּוֹב ״לְאִיתְנְסָבָא״ – דְּמַשְׁמַע לָא יִתְנַסְבָא, אֶלָּא ״לְהִתְנְסָבָא״.
And in the clause: And now [ukhedu] I have dismissed and ousted and divorced you, he should extend the vav of khedu, as otherwise, the vav may be mistaken for a yod, and spelled with a yod it indicates: And with nothing [ukhedi]. And in the expression: To go marry [lehitnasseva] he should not write le’itnasseva with an alef and a yod, as, if he leaves space between the letters it will indicate: Will not get married [la yitnasseva]. Rather, he should write lehitnasseva, with a heh and without a yod, so there will be no room for this error.
This reminds me of similar instructions regarding reciting Shema. In Yevamot 106, the same Abaye talks of being careful not to introduce pauses in the formula for chaliza (lo ava yabmi) because it could indicate the opposite (no! he wants to perform levirate marriage on me). In Sukkah 38-39, it is Rava who discusses not pausing in the middle of Yehei Shmei Rabba.
The thing is, maybe we are overdoing it. I would interpret this elongating of the vav as ensuring that it is not overly short, thus confused for a yud. Once it is the size of a full vav, maybe slightly larger but not even required, you aren’t making a mistake.
But, what about these gittin?
or here:
Elongating the vav that much transforms it into another letter, nun sofit, and a different word, כדן!