Only one of my runners has plastic shim-tape, so I use grease almost all the time.
I apply a thin layer everywhere the runner will contact the chock. The inside of my chocks are polished to about 1500 grit, so I'm very careful to avoid scratching them. I wipe it off and reapply every day (both from the runner and chock).
The best grease I've found is
Startbrite PTEF Trailer Hitch Lubricant. Its viscosity remains constant well below 5F.
I also use the stuff for my (non-ball-bearing) mast socket.