One would think that the WNY weather would allow for starting / reseeding during the summer. 88 is still very warm for getting the new seeds to germinate and properly watered. The new blades of grass are very thin, thus are very susceptable to stress. Watering a lot at this time can induce diseases as well. I have done the slit seeding thing as well, but I don't buzz cut the grass. I might cut the height in half. That way the new grass has a small amount of cover to keep it cool and moist. Don't forget to run the slit seeder in both directions for proper coverage.
If the area that is patchy and dry is small enough, sod is a great way to get it fixed in a hurry. Again, just make sure that it is properly watered.
I've become a proponent of core aeration as well. Once a year - in the spring.