According to this site:
https://bikecounterculture.com/2017/...er-calculator/ you are looking at 4 mm of difference, which, in terms of fender clearance, would only be 2mm difference. That seems like next to nothing, but if it's already tight clearance, it might be worth it to size down. I maxed out my tire size in relation to my fenders, and it was fine until I went through some mud. Then it was miserable, with me constantly stopping to clean out enough mud to move forward a little more. I do like a wider tire, though. If I were in your shoes, I might look at what my options might be for a fender with better clearance, or even one of those, under-the-downtube spray-catchers.