The 3/4" hardwood is going on the first floor (the only floor --- it's a Rancher). The basement is dry (a floor below). A french drain exists down there, so it has been dry for years. Why do you ask about the basement? I only ask because I don't know...
I'm not sure if I should put down plywood or not. Even 3/8" would raise the floor more. The subfloor is in pretty good shape, although after 50 years, it has expanded and contracted no doubt!
I have cracks in the T&G, and was thinking about doing the wood putty thing. 2 1/2" deck screws should handle the creaking in spots.
What do you think? And thanks for the response!
BTW, Can you send digital pictures on here?