This config-spec show the files I need:
element -dir * \'{version(/main/LATEST) && !version(SLT-T)}\'
element -file * \'{version(/main/LATEST) &&         
        
Did you try adding some query-language directives like:
&& !ver{created_since(1-Nov-2008)}
&& ver{created_since(1-Nov-2008)}
(all the versions existing before/after 1 Nov. 2008)
That is part of the query language and may help you refining your selection rules.
I confirm for having tested it:
element /myPath/... /main/{!created_since(01-Sep-2008)}
element /myPath/... /main/LATEST
would give you all version created before September the first in this instance.
I am not sure it can be combined with your rules to successfully achieve what you are looking for, though.
My point was just to make sure you can include time-based selection rules in your config spec.