Last fall I sent a sample of my drained
oil to Blackstone for analysis. The
oil (Mobil1 5W-30, 9qt pan) had 1,500 easy miles on it. Blackstone said it looked like it just came out of the bottle. If you're going to let the car sit all winter I would do it with a full tank of gas. Don't take a chance on humidity in the air condensing in your tank.
Bob