I did not ask myself such a question, however, when the font size itself decreases, the size of the line spacing also decreases, which can be observed in the text of the album description, for example.
In any case, you may need instructions from the author of the mod regarding the text, and yes, they will have to be entered manually, in every place necessary for this.
Code:
\-[XX]:Shortens spacing of following text by XX pixels. If you use a negative value for XX, text spaces out more.
\font[X]: Changes the font to sub-font X. \font[0] reverts to default font.