iMovie/iDVD resolution---what to choose?

I have 4+ hours old 8mm (color, no audio) that has been converted to VHS. I used an Elgato video capture device to put the VHS movie onto my Mac. The video was captured at 640 x 480.

I've been using iMovie to edit the movie---move clips around, add chapter titles, cut out poor quality stuff, etc---and now I want to share the project to iDVD. Since the film has no audio and was captured at relatively low resolution, the entire 4 hours is only about 2 GB, so there is plenty of room on a CD to hold it. I'm planning to share to Media Browser, so I can put more than one project onto the final DVD.

When I share the iMovie project to Media Browser, I am given the choice of resolution up to 720 x 540. My question is probably dumb. Should I share the movie 640 x 480 or 720 x 540. I know that choosing the higher resolution won't make the picture quality improve, but will it actually look worse to export a lower resolution movie to a higher res format? Or is it better to choose the largest format possible that "fits" for the medium?

I hope that makes sense.

Just because the file size is small, doesn't mean that you can get a 4 hour video on a dvd, assuming that you want a video dvd that will play in a dvd player.

A single layer dvd will hold about 1h30m of video and a dual layer about twice as much. In an iDVD Project, if you go into the Project Menu>Project Info, you can choose single/dual layer discs and also play with the quality to try and get more on the disc.

The dvd will be at 720x576 or 720x480 anyway reagrdless of the resolution of what you send it.

Thanks...I think that makes sense.I guess I don't fully understand why the files end take up so much space on the DVD---but if that's the way it works in practice, that's the way it is. I didn't realize you get so little time on a DVD. I've played around with the project that I created, and I'll probably have to break it into four DVDs if I make it on iDVD on the highest quality setting, if I use a single layer DVD.

In any case, I think my best bet is to export at the highest quality and take it from there. If I need to break up the project into multiple DVDs, so be it.