It is not a long article, but I picked up some ideas that I think can help us in further customizing MultiSearch:
Comprehensive Search vs. A Few Good Articles
UW Libraries put a "Find It Fast" box on their homepage with the idea that federated search engines do a better job of providing a few articles to start with, rather than being a comprehensive way to search all of the databases. If you really want the best articles, you really need to use subject headings and the specialized search features available by searching databases individually.
Select a Few Databases and Test
With this in mind, the article points out that it is better to set up MultiSearch by being selective, rather than comprehensive. In deciding which databases to include in each subject category, subject specialists suggested a few databases and then tested to see what kind of results came up in sample searches. Some databases provided only problematic results, so they were eliminated from the list, even though they could technically be searched with MultiSearch. UW has over 200 databases, which was whittled down to 46 databases, and finally after testing, they ended up with a dozen databases that consistently provided good results in sample searches.
Default to Title Searching
Serials Solutions sets the default to TITLE search. This seems odd at first (I remember as a Reference team we changed the default to KEYWORD). But TITLE searching works better than KEYWORD searching with federated search engines for two reasons: 1- Time - it takes forever to search the full-text of so many articles and databases. If we are offering MultiSearch as a fast option for a few articles, KEYWORD searching defeats this goal. 2 - if the idea is to get a few good articles, not be be comprehensive, then title searches will offer up a few good results with fewer outliers. Of course, some articles will be missed, if the topic doesn't appear in the title, but the point is not to be thorough, but to provide a few articles that are on topic.