DYS DD13 has always had the tiniest handwriting imaginable. She has excellent fine motor skills in all else (wins art awards plus seems to do her Chinese characters well). However, she is facing her first high school finals , and 2 teachers have indicated they are worried how her handwriting will affect her ability to take the tests. Her penmanship is fine if she slows down so I’m not sure what to do with their comments. Her previous 504 did recommend she use a keyboard for school work, but it was related to ADHD issues. Thoughts?

I wouldn't disregard advice like this without a strong reason. How does your DD feel about about it? How much of her energy and thought and attention (not just time) goes into keeping her writing legible (enough)? Is she writing with full automaticity or drawing letters as art?

Are the teachers recommending a tech accommodation for the exams? If so, what's the downside to accepting it?

As we have moved overseas, we have no one nearby who might assess her for handwriting issues. I wonder if there are some websites that might give me a clue as to how to determine this. DD can be fairly cantankerous when I start asking questions so I want to have an idea of what I might say before I interview her.

No, no accommodations mentioned. They just wanted me to know. It's up to me to do all the leg work. There are no downsides to accepting accommodations - I just need something to back up the need.

The simplest measure is to look at differences in quality and quantity of verbal expression when handwritten vs typed. Length of product (at it's simplest, word count), average length of sentences (proxy for complexity of sentence structure), complexity and elaboration of ideas. Words per minute. Those are a few of the elements I'd look for. There are a few other reasonably well-validated quantitative measures, but they're a little more laborious to record (e.g., correct/incorrect word sequences).