Quicksilver is no longer actively developed. However, issue number two
is already addressed with the TextMate Ranker plugin. Install this in
the plugins pane then change the string ranker option in the Handlers
section of Preferences.
The description claims it "prefers word boundaries", but what this
actually means is that it ranks names with initials that match before
names with consecutive letters that match. It would, for instance,
favor "Address Book" over "About these scripts…"
Hope this helps.