ClassicThesis text area dimensions for letter size paper

Question

I am considering using ClassicThesis (among other options) for typing my course notes. The problem is that ClassicThesis is customized for A4 (and A5) paper sizes, while I need letter size paper (8.5 in by 11 in or in a more SI-friendly way, 215.9 mm by 279.4 mm). I can change the paper size simply as

\documentclass[letterpaper]{scrreprt}

And as ClassicThesis is based on KOMA-Script, I can change the text area and margins using a set of commands like below as suggested in the package itself.

\areaset[current]{textwidth}{textheight}
\setlength{\marginparwidth}{length}
\setlength{\marginparsep}{length}

The question is what are the typographically correct dimensions to use?

A similar question is posted here, but there's no definite answer (well, expect for checking the guidelines given by Robert Bringhurst's book, to which I don't have access.)

PS. It shouldn't matter, but this is for a course in electrical engineering, which will include lots of equations and figures.

Answer 1

Try these sizes,

\RequirePackage[letterpaper, top=1in, bottom=1.5in, 
  left=1.5in, right=1.5in,showframe=false]{geometry}

I would try and keep the ratio of the text area to the paper area to around 0.50.

Here, is a minimal that shows the calculation of this ratio and sets the dimensions.

\documentclass[letterpaper]{scrreprt}
\usepackage{lipsum,fp}
\RequirePackage[letterpaper, top=1in, bottom=1.5in, 
  left=1.5in, right=1.5in,showframe=false]{geometry}
\makeatletter
\def\Htext{\strip@pt\textheight}
\def\Wtext{\strip@pt\textwidth}
\def\Hpaperheight{\strip@pt\paperheight}
\def\Wpaperwidth{\strip@pt\paperwidth}
\FPdiv\aspectpaper{\Hpaperheight}{\Wpaperwidth}
\FPdiv\aspect{\Htext}{\Wtext}
\FPmul\paperarea{\Hpaperheight}{\Wpaperwidth}
\FPmul\textarea{\Htext}{\Wtext}
\FPdiv\ratio{\textarea}{\paperarea}
\makeatother
\begin{document}
\chapter{INTRODUCTION}
\lipsum\lipsum
\aspect\par
\aspectpaper\par
\ratio
\end{document}

You can vary the top and bottom slightly to your liking, if you wish. Best is to try printing a few pages of real text sample, before you firm your dimensions to see if it is to your liking.