cbr or vbr1 when going xvid->dvd?

[charvelzeppelin]

I have about a bunch of movie clips that are around 45 minutes a piece. I am trying to fit as many as I can on one DVD but I'm not sure if I should use cbr or vbr1 for the bit rate. They are all xvid and I'm trying to convert to dvd. The movie clips already aren't that great of quality so I was just thinking about using cbr at 2500 and seeing how many I could fit on a disk. Would cbr make the files smaller compared to using vbr1 from bit rate 2500 to 9000? The clips do not have a lot of action so the bit rate would not vary much (would i really even notice the quality difference?). What do you guys suggest and how many 45 minutes clips do you think I could fit on a DVD? Thanks.

[charvelzeppelin]

nobody has any suggestions?