I find Emacs' scroll down C-v and up M-v a little jarring. I duckduckgoed (went?) around and found golden-ratio-scroll-screen but it didn't scroll 62% of the screen, as the README claims it to do -- in fact it overshot by a bit. As I don't have the time to debug it right now, what recommendations do you have to scroll half a page up or down on Emacs?