Getting all new items via the Open Platform

[Allen]

I was hoping to use the Open Platform API as an alternative to
following the Guardian RSS feeds. But I am not sure it is possible to
create a query that will give me all the items that have been added
since my last query.

Having had a look, the "start-index" query argument does not seem to
be related to the content id value as I first thought it was. And
there is no way to say "give me all articles with an ID greater than
X".

Also, because the "after" argument only has a granularity of days, it
does not provide a very good proxy for the above as I would get a
great number of duplicate articles as the day progressed. If I could
specify down to the second, then this might work.

Does anybody have a clever way to do this? Is it even possible? If
not, is there a plan to make it so?

As a fall back plan, does anybody know if the root level Guardian RSS
feed (http://feeds.guardian.co.uk/theguardian/rss) contains a superset
of all content published through the topic specific feeds?


Thanks
Regards
Allen