That seems like the wrong way to do it. The post sentence spacing was never really treated as two consecutive spaces - conceptually, it's a single area of whit

That seems like the wrong way to do it. The post sentence spacing was never really treated as two consecutive spaces - conceptually, it's a single area of whitespace that is larger than the inter-word spacing. If you especially cared about typesetting it correctly, you'd use a single   (or perhaps an  ).