There have been alot of good ways to try and guesstimate the final size of doing this one pass stuff but in my opinion there is no way to get exact estimates to fill the CD's all the time without doing sample after sample and ending up waisting more time doing that, then to just do a multi pass encode. The sample(s) choosen could be selected on the slow parts of the movie and miss the action so then would over-quesstimate the bitrate or visa-versa. With the speed PC's are able to encode now a days, I would just do the extra pass and be done with quesstimating headaches. My 2 cents
