Grit on TCG....
My experience shows two approaches:
* Nothing covered. Keep dry and vacuum everything out before moving anything
* All covered/pressurized. Still needs to be vacuumed before shutting down pressure.
Rubber covers + non pressurized or any grease/coolant on ways: Worse than anything else.
Think of rubber cover over a bar. You move the cover and increase/decrease internal volume of the bellow = differential air pressure and that surely sucks the grit inside the area that was supposed to be protected. And it is hard to clean the area inside the bellow.
I was thinking of fitting plastic "scrapers" on ways and pressurizing a small plenum right behind of it. Needs some trial and error, plastic "washer" pops out if too tight fit to rod and if too loose, uses a lot of air and blows the dust/grit around.
I would not worry bout the grit on MK I model, just keep it dry and clean.
BTW. Grit is going to be embedded on the plastic and wear out the steel rods. May actually make nice laps.