The Players guide is written for the 2.0 Engine. Attribute usage has been changed in the new engine.
From my own experiences with the GUESS reports - there is no such thing as "optimal percentages" for any rating. No single 'rating' or attribute weight can define a player, since different attributes are used, in varying degrees, depending on what kind of play is run. For example, outside runs would rely more on speed, inside runs more on strength. Unless you set your playbook to 100% Outside Runs, or 100% Inside Runs, you can't have an "optimal" percentage. It depends on which play is selected, and how you set up your play books.