I recommend going with the Home Depot chain option. You don't need the heaviest gauge, just something that will scare people off. As far as keeping it from ruining shirts, go to REI or any other outdoors store that carries rock climbing equipement, and pay about $1.50 for a few feet of climbing rope webbing. Total price of my chain lock setup was $14. The webbing also keeps the chain from marring the paint on your bike. Also, having a ****ty looking bike helps, at least for me.