Keep in mind I'm also running a pretty decent stretch on my tires for clearance, 215/40ZR17 to be exact. If you were to put something like a 235 on there then you would have some serious clearance issues. It also should be mentioned that not all tires stretch the same (obviously) and will offer different results. I'm a die-hard fan of Falken FK's on my stretched applications because their sidewall is great. Other tires, like Yokohama for example, are fantastic tires but don't stretch very well.
It should also be mentioned that not every wheel manufacturer measures their width the same way. Some measure from the inside edge of the bead seat on each side, others measure from the outside edge of the wheel on either side. For example my wheels are 17" x 9", but if you put a tape measure on them you'll find that the overall width is actually closer to 10".
As for finding exactly which sizes fit I would go off of some known specs (like mine) and compare them to both the stock specs and the specs of the wheels you are interested in. I personally like to use this offset calculator for my vehicles:
1010 tires Wheel Offset Calculator