After problems with 11.2, I've had some recommendations from the oXygen folks about the vmoptions file, which, combined with my own experience, give me these settings:

-Xss16m
-Xms512m
-Xmx2048m

As I work with 11.2, I'll revisit this if necessary. The word is that -Xss should never exceed 16m (and they say it would normally be as low as 1).