[support] setting different delta values for hook_block

[Scott]

I'm developing a module that currently does not use the delta value in
hook_block.  The view option merely displays a form for entering search
criteria.  What I would like is for certain pages on the site to provide
default search criteria and then display the search results.  My
understanding is that this can be accomplished by setting the delta
value.  I'm unclear on how and where to do this. I suspect this is a
theme setting issue but I have not found examples.