I would have thought there may be scope here for an 'evolving' model for Scott to follow, much as SONAR itself is now going to continually improve.
To accommodate this, my suggestion would be for Scott to make the move from print media to electronic media.
What is "X3 Power" on Amazon currently, $35? How about $15 down for the 'core' guide, and then another three or four updates as features are added to make up the balance?