You should aim to be at Jfk no later than 345. Delta suggests three hours, sixty minutes is the cutoff for luggage, checking in at the airport. If you aren’t checking luggage go right thru security. You can use a kiosk on the other side of security for passport verification or you can have it checked at the sky club or gate. How much time two vs 4 saves is somewhat dependent on your gate in terminal four. I personally always go thru four yes it can back up but I would say the longest I have waited has been 15 minutes. Yes the walk to some of the gates is long but it will depend on which gate you get as to how far the walk is.