It isn't possible to give a general answer - each typeface will require different leading (the space betweeen lines), depending on how high the glyphs (characters) are for each fontsize.
Best thing to do is copy a couple of paragraphs in your chosen font into another document, and then try out different leading values. 1.15 is a good place to start, do one paragraph in that leading, then copy the para and try 1.05 and again for 1.25, then print out and see what you think. Give the printout to a few people and get some feedback and fine-tune.
A quick look at the Wikipedia page on leading is worthwhile because these things aren't hard to understand, but can make a massive difference to readers' experience (and therefore future sales!) https://en.wikipedia.org/wiki/Leading#Issues
Best thing to do is copy a couple of paragraphs in your chosen font into another document, and then try out different leading values. 1.15 is a good place to start, do one paragraph in that leading, then copy the para and try 1.05 and again for 1.25, then print out and see what you think. Give the printout to a few people and get some feedback and fine-tune.
A quick look at the Wikipedia page on leading is worthwhile because these things aren't hard to understand, but can make a massive difference to readers' experience (and therefore future sales!) https://en.wikipedia.org/wiki/Leading#Issues
