I don;t believe the blocks aret nylon. I thought they were UHMW and have natural anti-friction properties. I lubed them on the 6 and did not on the 10 and notice no difference. petroleum based lubes, like grease, requires maintenance, as it eventually dries out and increases friction. I recommend no lube. I did have to work the ID's with sandpaper to get a low friction movement.
Larry