TeX, one of my baselines for good typographical rules, does not do a double space after sentences, but neither does it do a single space; it's more like a space

TeX, one of my baselines for good typographical rules, does not do a double space after sentences, but neither does it do a single space; it's more like a space and a half (unless you turn French spacing on, in which case it is just a single space). So I feel he's wrong on substance. Additionally Emacs uses it for sentence motion and that's important enough to me to retain the practice, particularly given that if I care enough about the typesetting to do it properly I'll be using TeX.