In general, > 4.5 Mbps will look good enough. High motion scene will require more than that.

From what I read, 100% quality in CloneDVD2 means no compression. So it should be 1:1 copy.

Of course DL discs or split across 2 discs will always be better since no compression is required. But this thread is about transcoding quality, I'm assuming the output will be in SL disc.