Two days on, and the fog is beginning to lift, thank you all. I learned a lot in a short time, and should be back in the groove again now.
I suppose it was good to have made some mistakes in he beginning, because it forced me to look at things and also generated this discussion.
The silly thing is, I have used the 3850 and the 4900 for years, and the issues of what feed is used and borderless or not also need to be addressed there. I should have looked at that. But for the past two or three years have exclusively used Enhanced Matt and Velvet, because they suited my subject, which means never changing ink and also using only one entry port.
I think I got it sorted now I even used a box of very old Canon FA-ME1, a Hahnemulle produced Museum Etching, 350 gsm, which I loaded from the front, choosing Legacy Etching as profile and as Media type, and it came out fine!