I agree that with the above sentiments that the various newer editions (and the requirement) are problematic. It's a business decision, one that does not favor the instructors or students. Although, I do appreciate some new repertoire, and the occasional improved fingerings.
The Guitar Series is an excellent resource. The best thing to do is purchase the Guitar Syllabus.
They also do not publish any accompanying material, though it's not too difficult to create a curriculum. (The Shearer books are just fine.)
If RCM wanted to really create something truly useful (and in turn, generate more sales), they would publish lesson books to go along with their repertoire and studies ones and the technique book.
I learned with Sagreras, which is very good, of course. But, it creates gaps if there is no additional material.
What can this strange device be?
When I touch it, it gives forth a sound
It's got wires that vibrate and give music
What can this thing be that I found?