I'm going to swap out the cassette on my Colnago Master XL to one with a wider range. I'll be taking it with me when I visit my brother in the next few weeks, and he has some pretty draining "rolling hills" where he lives. His suggestion is that I go with either an 11-27 or 11-28. When I talk to the mechanics at my LBS, they are not in agreement with which will function better with the Dura 7800 series drive train I currently have one it (Yes, I know it's a sin to hang Japanese parts on an Italian frame, but the DA is what was on it when I bought it.) One mechanic says the 7800 series rear dérailleur isn't really capable of dealing with a compact up front and a 28 tooth in the rear. The other says it should work fine. Any of you have experience with the 7800 series with a compact up front and 11-28 cassette?