It may also depend on how you are intending to have this printed. I have a banner of my character which is 5 foot by 3 foot or 60 x 36 inches which was printed by Photobox as I am in the UK. The maximum size that Photobox will allow for upload is 100mb so that stipulated my upper limit for the .jpg file I used. I cannot remember the size I used in Poser but I do remember that the render was close to 20 hours.

I was pleased with the end result, close up you can see some noise in the render but then the cloth used for the banner also has texture so this masks the grain to some degree. From anything over a foot away no grain or texture can really be seen and, as this is virtually a life sized figure that seems to be the closet most viewers get.

I also have a picture which is 30 X 20 inches and is on a special plastic in which the render is applied straight to the surface. There is no particular texture to the plastic so any grain/noise would be clear. Again the render took about 20 hours but as the size was smaller there is less noise. Again I was pleased with the result which stands up to close inspection, and it is clear the skin texture was for more important than any other factor.

This was the picture and the file supplied to Photobox was 7016 X 4960 pixels (8.770 X 6.200 inches at 800 pixels / inch) and 20MB.

 

 

I use Poser 13 on Windows 11 - For Scene set up I use a Geekcom A5 -  Ryzen 9 5900HX, with 64 gig ram and 3 TB  storage, mini PC with final rendering done on normal sized desktop using an AMD Ryzen Threadipper 1950X CPU, Corsair Hydro H100i CPU cooler, 3XS EVGA GTX 1080i SC with 11g Ram, 4 X 16gig Corsair DDR4 Ram and a Corsair RM 100 PSU .   The desktop is in a remote location with rendering done via Queue Manager which gives me a clearer desktop and quieter computer room.