[ppera2]

I can't agree with things mentioned in that article. Even with composite connection is very visible more sharpness in higher resolutions. Aprox. over 640 I don't see difference. For me. it looks that they talk about S-VHS and not S-Video connection.
According to that, that active line time is around 52 microsec. and max freq. by broadcasting is 5-6 MHz, horizontal res. can be over 500 pixel. Better analogue (studio) eauipment has more resolution (768, declared).
However for TV is irrelevant is connection composite or S-VHS - it is multiplexed in broadcasting, and what use of that, that it's later separated?
Advantage of S-video is mostly in that, that no interference between chroma and luma. Actually it's real useful for: TV out and for capturing from S-VHS VCR.

Back to resolutions: it's always better to capture in bigger resolutions, because capture itself will be more precise (oversampling). Loss, mentioned in article will be always lower if capture in higher res. Later you can resize to desired and to source best fitting res.
Of course that for lower res. you can use lower bitrate by capture.