Solved as in I got the package created using the steps outlined in my fourth post of this thread, thanks to easuter's reference to an intermediate directory and makepkg. I just used more steps than with the DESTDIR method.
I forgot to put (solved) in the title, but my fifth post was intended to express my satisfaction.
When the thread continued with "let's figure out why DESTDIR didn't work and how to fix that", I was happy to let the creative exchange continue and contribute what I could by being the tester. I know from personal experience, once a question enters my mind, it is hard to rest until I figure it out. As you said, there is always something to learn.