I wouldn't recommend converting directly to DVD rate MPEG-2: consumer hardware generates numerous artifacts, esp. when dealing with high contrast/hard edges video like the one you're likely to capture here.
Even if you record at the highest possible bitrate?
get a PVR card with hardware compression, use only highest bitrate (my Hauppage PVR PCI was ~15€)
I think using a non lossy software codec would be better option though..
My plan was to record either uncompressed or with a dvd record at highest possible bitrate and then re encode it to mpeg2 using software like tmpgenc on a pc or similar.
Where can one get a supervideo genlock these days anyways?