You're not trying to fit 6 one-hour videos on the same DVD, are you, Paulito? That certainly won't go!
From Vegas, export each video as a DVD-ready MPEG and use that as your source file for DVD Architect. Each one-hour video will fit nicely on a disc. As I say in my book, you shouldn't need any recompression if you don't try to put more than 70 minutes of video on each DVD.