I bought Saltillo tiles at a local stone yard (Bourget Brothers), which are a good substitution for quarry tiles, but if your tiles have paint on them, I would turn them upside down. Also, you might want to use a pizza screen, which is what I do just for convenience. I use a Saltillo tile (which I cut down from 12x12 to 12x9) in my toaster oven, but I have a regular pizza stone in my regular oven. In the regular oven, sometimes I use a pizza screen and sometimes I don't, and I like the results pretty much equally either way, but then my regular oven will not get as hot as I would like.
What baking temp are you using?