What size of font type do the letters of recommendation need to be?
The only thing I can say about the comment font is that it should be noticeably different from the main text font. I think it’s obvious why. And there’s no point in me answering that question. When reading long texts, it can be very frustrating to see a comment that is not marked differently. At the very least, use a signal word like “here’s a comment” or something like that. The worst thing you can do is use a logo font; don’t ever do that! I mean, they’re pretty, like my hero academia logo, but these fonts aren’t for writing. They’re for logos!