I wouldn’t mess with the paper thickness in the Alignment menu.
Here are the specs for exhibition Fiber
325 g/m2 ... grams per square meter. This is the “weight” of the paper and offers an idea of how “heavy” or “thick” the paper may feel in hand. Sometimes it is listed as gsm, grams square meter.
13 mil ... (12 mil for rolls). The actual thickness of the paper. To get a useable number in the printer driver this needs to be converted to mm, 13 mil is equal to .3306 mm, 12 mil is 3.048 mm.
(I assume in your example you meant 19 mil and not 19 ml unless perhaps ml is used on other languages in place of mil, to me ml means milliliters which wouldn’t make any sense. A 19 mil paper is .4806mm so I would use a setting of 5 for the thickness).
The default of 3 in the printer setup is close for EEF, but personally I use 4. Just found I have less issue with surface defects.
Platen gap is the space for the transport mechanism, so changing the paper thickness moves the entire transport assembly(head and platen). Platen gap allows more room through the transport mechanism but does not move the head. After getting the width set correctly, forcing the platen to a wider setting can help with roll papers that tend to curl and contact various surfaces when moving through the printer.
Some other things that can help with issues like this is a little more suction to help keep the paper flatter (although this may also cause other issues) and indeed slowing the printer down by using unidirectional and even allowing a slight drying time per head pass can help, allowing the ink to set and dry before it contacts the offending rollers in the printer.
Finally going through the printer and making sure there isn’t any buildup on any of the surfaces might reveal some issues. It doesn’t take much to scratch some of these papers.
Pretty easy to find out if it is the paper, you should be able to see the scratches before they it goes through the printer. They will be hard to see but should be there.