I'll second liquid urea.  It won't burn the wheat where a 50/50 mix of UAN and water will burn.  Also, higher nitrogen rates on winter wheat will make more bushels until protein gets to 12% or so, after that more N won't help yield but will start to add protein. So, more early season N plus a minimum 10-12 lbs/A sulfur will help maximize yield and help protein.  Liquid urea is a good option in a wet year when you know protein will be down.  You can always skip it if the wheat has heat and drought stress during grain fill.