Arenhaus, thank you for putting so much effort and thoughtfulness into tackling my question.
It is extremely helpful.
For my purposes, I have the following take-away, and I'd like to see if you concur.
Following is my take-away:
I am making paintings for output at commercial inkjet printers at 36" X 24" or larger.
They will hang on walls for viewing at normal distances. If I
1) build my paintings in ArtRage at 150 dpi (or 200 dpi?), I can safely let my commercial inkjet printer use the exported PNG file and the image will look fine to the average viewer?
2) ensure my dpi and canvas dimensions have been properly set in ArtRage from the beginning, and
3) export to PNG without any rescaling
Is this a correct assumption to draw from your input, or have I misinterpreted your salient points?
Thanks again. I very much appreciate the thoughtfulness and thoroughness of your previous response.