13x7, 14x7, 15x7, 16x7, 17x7 even 18x7 fit well. The tire height is far more important -- with larger diameter rims, you'll need lower profile tires.

Use offset +25. Some guys like less offset, but then it will need flares (or stick out of the fenders). Less offset is good for narrower rims, as it will move the rim face outside to the body edge. But with 7" it's going to get there anyways.

The stock B310 tire was 155/80R13 which is 22.8" high. A 195/50R15 will be almost exactly the same height. You can probably go with a bit larger diameter, look at how your tires fill the wheel well now. I wonder is 225/45R15 will fit the back widthwise (it's just a small bit larger diameter than stock)?

You should do a trial-fit before buying wheels and tires for this close a fit. To make sure they fit in the wheelwell and don't interfere at full lock turning.