Thank you. Yes, my next option was the commit option. I’ve created many very complex images from scratch via Dockerfile (i.e. pure Infrastructure as Code that I can check into GitHub/GitLab), but this one is a real pain. I may still do that, but for now a commit-based or tar-based “image” will do for MVP / Prototyping. But I concur with your general point of view. 
Thanks for the reply!