Thanks. I've been lurking xda for a couple years now; most of their stuff is out of my wheelhouse but I use the bits I need and can use periodically.
I knew about the system image but didn't know how to obtain that; thanks for the info regarding an extractor. The device I'm going try out is a spare free pixel, so it's fairly ubiquitous for stock images and apps.
Thanks for the quick tutorial, I wish more Poalers shared their knowledge with each other!