Let it cut. I do it all the time with Photorag, German Etching, William Turner 310 grams.
Keep your head carriage bar oiled, replace the belt when it gets old, put in a new disc knife when you think it is getting blunt but use the machine as it is intended.
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Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htmDecember 2012, 500+ inkjet media white spectral plots.