One more question...there are a few low spots in my lawn I'd like to level out, should I just put some lawn soil in them and even it out with the rest of the lawn and then seed over that?

Search this forum for topics on leveling. Usually those pertain to bermuda which can be mowed super low and still recover quickly. After you read about it, then ask your question again. As to topsoil, it must be pulverized to work with a drag. If you don't use a drag then cloddy topsoil is fine.