Suggestion: Custom zoom

I find that sometimes, depending on how the text is on the original comic/book, fit to width makes it too large, and fit to height too small. I usually just set it to width and play with the browser window size on desktop, but I don't have a good solution for tablet. It would be nice if one could have a "Custom" zoom option and (+) and (-) buttons, so one will set the zoom more precisely. Thank you!