Pretzels - Which pan to use?

Hi

One of my favorite recipes I have found here is

http://www.thefreshloaf.com/node/4716/amish-soft-pretzel-recipe-request

However, I am not satified with using a cookie sheet to bake these. The bottoms sometims stick or come out improperly cooked. I was thinking of switching to a pizza screen or perforated baking sheet. Any suggestions?

I am hesitant to cook these on my baking stone (Williams Sonoma one) because I do not wish to expose it repeatedly to the pretzel dip (baked Baking Soda and water). I hope to switch to lye in the future and want to get away from aluminum as well.