Font size is important in how easy a book is to read. If you make your font, say, size 14, you'll not only add a tremendous number of unnecessary pages to your book (and cost of production) but old will people love it. Balance that to your own (or your reader's) satisfaction Choose a font of no more than 12! Please. If you'd like to be popular with your publisher but you'd also like to try a new font to make your work easier to read, type a full line of text in Arial 11 and then right below it, compose the same line in your new font. Adjust the new font's size until the lines are roughly equal. But notice how long the line of text has become. Is it longer? Shorter? By how much? Endeavor to keep it within a few percent. Less than five? If it's longer, you turned your 300 page book into a 315 page book if the test line is 5% longer than Arial, size 11. Arial is pretty spaced out and easy to read but it has no serifs so it is fairly bland. Times New Roman was cool looking in the 1990s but has kind of died out. Garamond is a great font and easy to read except by the elderly. The letter shafts are very thin and the serifs are tiny, but enough to add a bit of almost unnoticed elegance to your words. It will also shrink your manuscript by a good 12% which is useful if you have a page limit for a writing contest/award, but not a word limit.
I'm befuddled. If you have a publisher who's aware enough of you to approve or disapprove of you, they'll choose the font.
Do you mean for submission? Guidelines often mention that font size 12 with seraph characters double-spaced is preferred. As for publication in print, the publisher will decide. For eBooks it's irrelevant as everyone can set the font and size they prefer on their device. I use Garamond or Times New Roman 12 for submissions. Never Ariel for hard copies. Anyway, this is why publishers go with word count and not page count, like film. Film scripts must be 12 Courier or 12 Courier new. Anything different will not be read. That leads to consistency so page count is a good guide. For prose, due to the differences in font selections and spacing, kerning etc, word count is all that matters.
I think the publishers would like it more if you used 12 pt. font with seraph characters (ie, Times New Roman, Courier New) and double-spaced. Though I need to ask, what's the difference between seraph and non-seraph font? I'm aware they look different from each other, but the meaning of those two words I'm not so sure of.
The seraphs are the little tails on the letters that help the letters flow from one to another and makes reading easier, usually print reading They are on the font used as you read this). A sans seraph font is a font without seraphs, such as Arial, and is often used on screens, such as emails.
I quite often use sizes 48 for series title, 14 for captions, 26 for volume title, 28 for the "written by" or "written and illustrated by" part, 28 for Table Of Contents, 26 for chapter titles in the table of contents, 36 for chapter titles at the beginning of chapters, and 28 for the chapter itself. The font I use depends on what I am writing but I will often use something similar to Times New Roman or Courier New unless it is like a story about me exploring the human body in which case I use the Chiller font. I will occasionally use other fonts but that is usually in the decision of what font to use and not the font that I actually use.
