Digital BW, The Print

I'm getting those tiny white pin prick tracks down the length of my
prints (only on the black ink areas; lighter regions are fine) on an
Epson R2400, and on all of these papers: Ilford Gold Fibre Silk,
Hahnemuhle Fine Art Baryta, Innova semi-matte. It is obviously the
pizza wheels marking the print. I've written Epson customer support,
but they tell me that if it's not happening on Epson paper, they can't
(won't!) help me. I am using the semi-gloss setting and an excellent
custom-made custom profile for each the papers. 

I've tried to print using the thick board feed from the front, by
putting the paper on a 1mm thick board, but the paper slips on the
board, and the results area always horizontal bands, so that's not a
viable alternative.  

My next plan is to get a package of the Epson Exhibition Fiber paper
and try that. And once I've bought their insanely expensive paper, and
the tracks are still there, then try customer support again. But I'm
hoping I can find some other help before I go that route. Anybody got
any ideas?