[[DefaultTiddlers]] can contain a *list* of tiddler titles (and/or tag
filters), stored as a white-space separated list of titles.
To open several tiddlers, simply write:
[[SomeTiddler]] [[SomeOtherTiddler]] [[YetAnother]] etc.
For your purposes, you can just combine the code for the two pieces of
text you already generate, like this:
config.shadowTiddlers["DefaultTiddlers"] = "[["
+ store.getTaggedTiddlers("journal","modified").reverse()[0].title
+ "]] [["
+ new Date().formatString("DDD, MMM DD YYYY")
+ "]]";
enjoy,
-e
Eric Shulman
TiddlyTools / ELS Design Studios