schema arrangement or architecture

Hi,

Given the "salami slice" style of schema (all elements and types are
global) are there any established practices for arranging a large
schema? eg

- try to keep to one large file or break it down into several files?
- ensure all element definitions are always in a single file, or where
possible keep element definitions in the same file as their type
definitions?
- should all attribute be defined globally?

etc.

There seems to be quite a lot of information about the different
schema styles out there, but not much on managing a large schema...
(in this case I'm calling a "large" schema one with just over 100
different elements each with their own type... ~150 attributes)

Is the secret of maintaining a large schema down to good tooling
rather than an intimate knowledge of what's in each file?

thanks
-- 
Andrew Welch
http://andrewjwelch.com
Kernow: http://kernowforsaxon.sf.net/