Most of these episodes are often found "remastered" by youtubers. These youtubers are usually arseholes though, so good luck getting HQ videos. Also, they don't even crop the picture - they just stretch the previously existing 4:3, and it looks horrid IMO. Personally, I'm far more interested in the original DragonBall dub. Not only is that script different from FUNimation's, but it's also much harder to find (Nyoibou is used, as is the "Son" family name).

Many of the videos that don't simply have synched footage from a DVD have foreign subtitles and are of dubious quality.

GT is not quite as hard to find as DB, but it's harder than Z.

That being said, if I could help let me know - I'm also interested in this project. Similar projects have been attempted at Daizex by a member calling himself DBZOceanHD. He's also the Kai fandub guy. You can find the few episodes he completed here