Size required not updating when ripping and taking out streams in Smart Ripper

[sidders]

I am using SmartRipper to backup a movie onto DVD-R. Obviously, if the diskspace reqired for the main movie is bigger that 4.7Gb then I have to get rid of some streams (subtitles etc). If I go to Stream Processing and untick some streams, the size required on Hard Disk does not change. Without actually carrying out the rip, how can I tell if this is enough to get it below the right size?
Thank You

[LIGHTNING UK!]

Programatically, there is no easy way to tell how much is used up by the individual streams. Its just a case of guessing really.
Im sure if time wasnt an issue, someone would come up with some sort of formula. Personally, I didnt bother with it.