$12 Anti Door Ding Device

I just punched holes through the tubes and tied knots in the nylon parachute cord. Since both sides are the same, the weight balances out and you can easily adjust either side up and down. The ropes are just tossed over the car cover. I think those big swimming pool 'noodles' would work better, but I was at Lowes and saw these and the gears in my head started turning.

That happens to me all the time where I see something in a not auto related store that will solve a problem with one of the cars.
That is exactly how I ended up finding out that the shop vac replacement hoses made good defroster tubes on the A bodies.
You can even heat them with a heat gun to make them hold curves and corners for a nice clean out of the way routing of them.