I generally like to have my DivX movies on one CD. This helps me reduce costs and clutter. I have noticed that with some movies, It is just impossible to put in on one cd. I have found Gordian Knot to work nicely to help me determine if my movie should be more than once cd with its compressablility check. I have not made that much divx, but I was wondering if there is a general length that people look to figure out if they should make their movie 2cds or one cd.

Compressablity check is the only way to know if it will fit on one CD or two. I've had a 2 hour and 20 minute movie fit perfectly on one CD, while on the other hand, i've had 90 minute movies need two CDs. You just cant tell by the time length of the movie.

doh, and I thought I finally figured out a way :(

where can i.... 

i am new to GN, and have tried using the compression check but dont really understand the results, where can i go to find out how to apply the results to making the 1 disk or 2 disk decission? i just use this; 110 mins = 1 cd 110 + mins = 2 cd thanks in advance

If you go to the Doom9 Guide for GKnot, it will tell you how to interpret the meaning of the Compressability Check...