Hi Paul. The S-Works Roubaix SL Dura-Ace 2007 uses this cassette with a short cage and compact cranks. I have not experienced any problems with this setup. I find it easier than on my previous bike with 53/42 and 12 /23 cassette.
My Giant Cadex is running that combo with a short cage rear derailleur - works fine. I had to lenghten the chain by 1 link which was easy done.
Yes, it will work without any trouble. In fact you should be able to go to 28T which I have fitted to several bikes running 105 and Ultegra. Which rear derailleur do you have?
105, but will soon upgrade to a dark grey ultegra to match the cranks.
Was running a 50-34 with an 11-28 no issues on my Cannondale and Ultegra Derailleur
A mate was running 50-34 with 12-27 on a BMC with 105 no issues, changed it to a 11-28 still no issues.
I use this cassette with standard 52/39 chain rings, and short cage Ultegra derailliuer with no problems. Shimano's recommendations assume that you will be using the extreme cross-over gears, which should be avoided anyway.
Is chain length an issue when stepping up an extra couple of teeth?
I went from 25 to 27T with no change in chain length.
Chain length would only be an issue if its been adjusted too short when in the big ring / little cog position.
If the chain length is OK from the big ring to the second last rear sprocket, it will certainly be OK from the small ring to the 27T
how long is a piece of string?
Or in this case a short cage derailleur.
What size parallelogram on this derailleur?
Without information on the derailleur it is hard to say.
In the big front and big back combination doss there appear to be some extra slack that can be taken up?
Is the chain long enough?
So many questions so few answers.
It is not a big job to take the cluster off to give it a test if you have access to a 27 or 28 tooth cluster.