This is how I've set it up:
keyword -> Launch Apps / Files (with my selected files) -> Run Script
where the script is Language: /usr/bin/osascript
and the script is as follows:
tell application "Moom"
arrange windows according to snapshot named "MyLayout"
This assumes you've set up a Window Layout Snapshot in Moom called "MyLayout" & which is appropriate for the selected files.
I've set up custom snapshots on all three of my machines for the optimal