Longer reach with less drop might not be the end of the world.  I'm surprised your TT is so short, Mike.  Mine on the Roubaix is 582mm so I wasn't so freaked out by the 59cm, but if the Gunnar has a 54.5cm TT that would seem really short for a guy your size - in my head anyway.  Are you sure you aren't thinking of the seat tube?