OP here. Glad you got your printer functioning. It is good to have an army of techs. But I have had no scratching issues save for the Hahn Gloss Baryta, and no other. Since posting I have made some printer setting changes that appear to have reduced the phenomenon - widest platen gap and increased paper thickness from 3mm to 4mm. I may go to 5mm if necessary. A shame, really. I have made the paper route, and this paper, for my tastes, is just unsurpassed.
David