As for the non-torrent related questions, you can download imgburn here: http://www.videohelp.com/software/ImgBurn

The above site has a link that says AdFree, so just use that. I believe the other links are valid too, but one needs to be careful to uncheck the other stuff it tries to get you to install.

4.7 gb discs are what you want.

Also, you're right. The DVD5 versions are *not* easy to find on public trackers it seems. I could've sworn I saw them once, but I wouldn't be surprised if they died off.