I have had good results with all the stoneware clay bodies I've tried (four). I tend to stick to a stoneware with more grog in it. Since it's more robust all around I feel like it will be more tolerant of baking as well.
I have done a lot of reading and research on baking dishes. Some people have said to leave them extra thick, and others say that it doesn't matter if they're thinner, it's just that the walls and bottom must be about the same thickness and without a sharp angle between the base and walls. I can't remember the reason precisely why this helped it to be stronger and handle thermal shock better. Perhaps that it was more of one surface rather than two surfaces joining sharply together? So even on the ones I've made with straight up-and-down cylindrical sides I make sure that there is a gentle little curve connecting the base to the sides rather than a sharp corner. And that's better for baking with anyway! I trim the exterior to follow the interior.
Either way I have been making slip cast and now wheel thrown pie plates for several years. The first few that I made were given to friends and family to quality test. The reason that I believe the information about it being okay for the pie plate to be on the thinner side as long as the walls are even is that the Duncan pie plate slip mold that I have makes a pretty thin pie plate. I model the ones I throw now off of a similar thickness.
I send a use and care slip with every one that I have sold or given away. I basically give instructions similar to the way you would use a glass baking dish. No temperature extremes. Don't plunge a boiling hot baking dish into water or take something from a freezer into a preheated oven. Common (or uncommon) sense.
Again if I'm recalling correctly, there cannot be cracks or pits or bubbles or imperfections in the baking dish, even on the outside, because if there are then they become weak points that lead eventually to cracking.
Last note: I often use my stoneware bowls and plates and other little dishes I've made to heat food in the oven, and they're just lovely. I've been slowly replacing all my metal and glass baking pans with ceramic ones. I usually buy the largest ones just because I don't have the kiln for them but even a very cheap ceramic casserole dish is better than the best metal casserole dish in my experience. One of these days, try baking half a batch of brownies in a ceramic pan and half the batch in a metal pan and you'll see.