By the way, I also use Studio 12 and when creating the DVD image I always use 100% quality. With this quality, Studio 12 will not re-encode the MPEG. Which means that:
a) the quality does not change from the original MPEG recording (note that I record only using MPEG; not AVI or any other format)
b) I do not lose any closed captioned text (this was handier before I got a blu-ray player though...)
c) the DVD creation does not take forever
One other thing I have found is that Studio is overly conservative when it comes to estimating what will fit on a DVD. According to Studio, my 82 minutes of standard MPEG video will not fit on a single-sided DVD - it claims that I have around 20 minutes of overflow. So I tell Studio to create the DVD image on disk only and then use a DVD burning package (I use Nero) to burn the resulting video files to the DVD.
The resulting DVDs are good enough that they look fairly decent when played on an 1080p HD TV, as long as you don't look too closely.