i encoded akira onto 2 cds and the estimate came out a little above than what the bitcalc said. so i had to cut off the intro
from experience, i found that it's always good to take off 10 or 20 bits of what the calc says. this way, my movies always comes to be just the right size or smaller. i encode a lot of anime and i find that it's always better to do 2 episodes per cd than trying to cram 4 episodes. this applies for most animated anime (ie lain, princess monoke) however i discover others, such as kenshine (tv series), where the anime quality isn't so great to begin, it's possible to put 4 episodes per cd without degration from the orignial. just my 2 cents...
btw i use divx4