You don’t ask a rabbi, a scholar or any adult.
Keset Hasofer 6:1 reads ‘For every letter where there is a doubt that perhaps its measure is such that it would be considered invalid or perhaps it does have the right form that it would be invalid, we show it to a child that is neither [especially] clever or a simpleton, and if he knows how to read it according to its rules it is valid. And this is only when we [really] doubt [that] the discernment [of a child] is of use.
I had been fixing the section in Noach about the rainbow and came to a case of genuine safek (doubt) involving one of God’s holy names that you are not allowed to erase - Elokim - see picture above. Basically the yud is a bit too long and resembles a vav. You can see the problem when you look at the other Elokim on the next line down. Not quite a vav, but not really a yud either as its leg is too straight and too long. Consulting Or Hamelech, Otser STaM & Keset Hasofer saw the halachah coming alive before my eyes. and I concluded that I could only take appropriate action once I got havchanat tinok - the opinion of a child who is neither too clever (i.e. they could work it out from context) or too stupid (they don't know the letters at all).If the yud is pasul and is a vav then the shem (name) isn't a shem (even though the scribe originally may have sanctified it). Two options - either add a lot more ink to make it a yud rabati (don't like that option as looks awful - the pic in Or Hamelech is terrible and wouldn't really work on the itsy bitsy torah as the spacing is very tight) or erasing the whole letter being careful to ensure at no point it comes to look like a yud, so either from the top of the regel (leg) or the whole rosh (head) and regel (probably go for the latter as the thing is so small even a tiny bit of regel left at the top could make it look like a yud) and that would be chok tochot (carving around to form a letter) and letters must be formed through the act of writing.