Nice progress you're making JAF. With few exceptions will you find the Saguaro near red rock. That exception would be 'Red Mountain' northeast of Phoenix. That mountain is a dark reddish brown unlike what you would see in Sedona.
For the most part, the mountains around Arizona have that reddish/brown with a tad of purple shade. The heaviest stand of Saguaro that I have seen is around Waddell en route to Wickenburg, Arizona northwest of Phoenix.
Looking forward to seeing your work in progress.