Seems all setting are taking into account media to only fit on 4.7gb, right?
What's the setting for an 8gb disc now? Seems there's no presets for that. Thanks.

Just (slightly less than) double the time! The times are just to give an indication of what will fit on a DVD5 and you can compress whatever you want with any of them. Single/dual layer is selected whilst authoring in DVD SP - if it won't fit on a DVD5, you need a DVD9.

There is a Mac editing forum which would be more appropriate for this thread.