You could just taylor the compression for the filesize you need.
I think you can comfortably fit a 620Mb file on a 74min CD allowing for the filesystem so you just work it out like this :
BITRATE = (620 / TIME IN SECONDS) * 8192
Using that formula you could encode a 90 minute movie as a 620Mb file by encoding with a total bitrate of 940Kbps. Because you'd be encoding the audio in MP3 format with a bitrate of 128 - 256Kbps the only variable when you encode various lengths of movie would be the Kbps of the video compression.
Hope this helps.
... and barkmonster looses the 12.20 race by a long shot