from what I read 75-80 characters per line should be the optimal for the human eye to scan. Leslie Lamport makes a mention about this: https://haroldpboas.gitlab.io/courses/math696/LaTeX-customizing-page-layout.html
I'm currently using the Charis SIL font at 11pt and 1.5" left and right margins. A4 paper.
Page 1:
Page 2:
I'm not sure how tall should be my top and bottom margins. Is there any rule to follow on how many lines per page should be optimal? At the moment I use 1" top and bottom margins, but as you can notice there are many lines on the second page.