I would think that since you need both the tires and wheels, you should go back to the OEM tire size and wheel, P245/60R18. You should easily be able to find the 18-inch wheels at your local salvage yard. If you want to go with a 17-inch tire and wheel set up, the tire size that has the closest tire height (to reduce speedometer error) while increasing the sidewall size from 5.8 to 6.3 inches is P245/65R17.
For your leaking tires, try replacing the valve stems. Some stems are known to leak.
Doc1.pdf