getting seed list for vertical search engine

[DS jha <ae...@gmail.com>]

Hello,
We are in the process of developing a vertical search engine for the
medical industry – and I need to estimate server/sizing requirements
to setup my environment – my question is, how do I estimate how many
documents I will be fetching for a particular vertical?  And – from
where do I get the seed list of all the sites? Will dmoz health
category be sufficient or will I have to purchase a seed list?

Thanks