CG animation movies (Final Fantasy, Monsters Inc, etc) should probably be treated just like any other clean dvd source (unlike older cartoons/anime, CG is very clean)...you'd use the current Optimal Script and the same methods as described by any of the relevant guides available here. You really shouldn't need to lower the GOP since this is recommended mainly for standard 'toons...but you can certainly do a comparison with your own eyes if you're not satisfied with the quality you get using the standard kvcd GOP...filesize will increase though, so it's up to you whether or not it's worth it.
This issue has been discussed here a few times before....doing a search for "cg animation" turned up a number of hits, including this one:
http://www.kvcd.net/forum/viewtopic....t=cg+animation which basically repeats everything I just quoted from memory, so this must be the exact thread I was thinking of! The Search button found at the top of the page is quite a handy-dandy tool indeed!

As Obi-Wan Kenobi might say, "Use the search Luke....always".

(Yes, I know, I know...I'm a geek

).
Good luck,
-d&c