Wider is better than a lot of people think. Faster, more comfortable, more sure-footed, more versatile.
2.3's.
Maybe even a bit larger.
Ms. Cools has something to say on the subject:
Henry Wildeberry explains the choice of tire size in the comments section below the video (in answer to a question by Rudi van Desarzio).
Ms.Cools talks about why she likes those tires and their size in another video. She says they are a bit like riding on pillows, among other things.
In my experience, wider is much better on gravel and rough surfaces, and not slow on pavement.
There seems to have been a longstanding prejudice toward narrower tires. It's changing somewhat, but it seems to me that a lot of people are still reluctant to go "too wide" when it really isn't too wide. So even if they are open to somewhat wider tires, they aren't open to taking it further.
Henry Wildeberry has another video in which he does the math, with results that also point toward wide-phobia as a widespread syndrome. He has an engineering background, and his analysis supports the choice of wider tires.