I'd be a little concerned about a 52 minute connection at JFK if it were to turn out that you had to change terminals. IME you can't predict where your domestic leg will land - I take the same flight regularly to JFK and it's a toss-up as to whether we land at T2 or T4. If your domestic flight is on a RJ, you'll probably come in to the RJ corral at T2, but I don't even know if that is guaranteed. But delays are always a strong possibility at JFK, and if there's even a brief delay in getting in, and if it takes a few extra minutes to get to the other terminal, and if you have a long walk to your gate, etc., those 52 minutes can disappear pretty quickly.