I drove around with this set up and snow tires on the stock wheels. I had no issues during heavy snow and iced roads. I drive 30 miles daily to work.
The sand and tool boxes were purchased at home depot. The bags of sand had real thin plastic, the tool boxes were a precaution to contain the sand, in case the bag decided to tear, it also made it easier to take out the weight, if the roads were clear and there were no huge storms on the way.
After driving around, 1 box of sand is all that is needed. I placed the box centered over the rear axle. I also have the trunk carpet liner, which I turned upside down, the rubber gripped the sand box, the box never moved around.