Thank you for you input Jocelyn and Christian.
much food for thought.
I have never really thought about object hierarchy but, if I understand correctly, it is possible to have a 'parent-child' relationship between applications (have I got that right?).
and this means that a data object created in the 'parent' application with Application Component access level should be visible in the 'child' applications.
the bit about the structure of projects (one big application versus many smaller applications) is something I am still struggling with. On one project I was involved in (although it did have several applications in it) the response in the workbench was glacial (literally minutes between mouse clicks) - we are in the process of refactoring this project.
Catalogs - I have not had much to do with so I do not really appreciate their value. I have come across enthusiastic comments about them in various discussions and blogs but I have not had the opportunity to investigate them.
so, my take from this is:
- global is ok but it may come with a performance hit
- Application Component access may be better
- be careful how projects are structured.
once again Jocelyn and Christian thanks for your input.