When reading books that include English, Hebrew and Greek fonts, I've found that the Hebrew font is too large compared to the other two fonts. The English and Greek are well-sized, maintaining a good correlation when I increase or decrease the font size for the book (which automatically adjusts all fonts at once).
However, the Hebrew font is larger than it needs to be - for my sake. I think it could be reduced by 10-15% to start. Alternatively, we could have the ability to change the default size of the Hebrew font in program settings.