Holy cow I didn't realize I was losing so much bandwith to sound with the PCM setting. Yeah Dolby Digital seems like a better idea (I also have the Mpeg option). Might be why I never got that great of a result with long projects.

MP2 audio does compress more than PCM, but it is not part of the official DVD spec like PCM and Dolby Digital are. Still, most, if not all DVD players do support MP2 audio. But if you have the ability to use Dolby Digital that is the format I would recommend.

ac3 audio is more compatible than anything else you can use on a dvd.

if your program is over two hours long, the nature of the footage will be critical to whether or not the finished quality is acceptable... along with the encoder you use, of course.

the object here is to first improve your skills as a compressionist, instead of throwing money at a hardware solution that may or may not work correctly.

you can use the bitrate calculator at www.videohelp.com to determine what the average vbr setting should be... the peak vbr setting should not affect the final size of the file, i typically use 8700-8800 for that.

Bitrate Calculators
 

I found this calculator to be helpful. There is no install, provided your browser has java installed.

http://www.videohelp.com/calc.htm

For downloadable programs, try this page:
http://www.videohelp.com/tools?s=1#1

-DB