Activist Search Engine - Using Google and 5000 Sites

I've been collecting a list of activist websites, primarily english speaking from the US and Canada, for my conference finding bot.

Here is a customized google search that uses those sites:

http://www.google.com/coop/cse?cx=006452045356193133822:sp984foeerq

It seems to not have as

It seems to not have as complete an index as using the "site:domain.org" command on google.

For instance, if you do a search for all the pdfs on seac.org (filetype:pdf site:seac.org), it comes up with 1/4 the number that you get if you use the regular google.