great idea. i too have literally hundreds of tires lying around where i live.(racing family) i will give your idea a try this weedend. looks like i should add an extra row of chains to reduce blow through.
I used a 235 r 15 . The chains are 20 in at the top the distance between the top side wall holding the chains and the top of the basket is 21 in. I measured a regulation basket and built my tire basket to match. Post some pics when your done