ink,
for my taste i do the same like you but changing the passes:
we have to use an source size as reference.......8Gb size of the source.
i don't like original menus. the kdvd autoplay and only when i need or want, i call for it.
i don't like the menu first waiting decisions, the decisions was encoded like i choosed...only my taste ...i don't like to start with menus! (this is the real reason why i don't use dvd-rb)
than...
1- encode that 8Gb source to get 6Gb (audio without re encode)
2- author in tmpgencdvdauthor to build menu/chapters
3- transcode the resulting author in shrink to dvd media size.
following that steps i got better results than doing differents steps.
means:
8Gb encoded to 6Gb and author, then tanscode to kdvd media size =
less looses than others options!
i did long tests using the hulk as source in all possibles variations.
..that was the best option that give less looses.
it's cool for my taste