Thanks for all the advice. I went to my LBS who suggested I not switch to an 11 -28 nor change to a mountain bike derailleur, but instead keep the same derailleur and switch to a 12 - 30 rear cassette. Lower grade however, Shimano does not make a 12 - 30 in Dura-Ace. Hopefully, I will have a few more gears when I need them for the hills Thanks again.