I mark a script like an exam, and I try not to do anything under 50 per cent. Similarly with the part. And also film is a peculiar thing, parts don`t necessarily read in script form anything like as well as they can do when it comes to materialising.
I am not an enormous believer in research being the be-all and end-all. I get suspicious when I read about actors spending six months in a clinic, say, in order to play someone who is sick.