Well, everything went well with this setup (30T inner ring) . . . even tho Shimano rates the dr to 27T max on the cassette.
Up until a few years ago, I had a Bianchi with an Ultegra triple 9-spd derailleur that a LBS made work on a 32T cassette (30T inner ring). It worked fine but not not in big-big (which was a little scary as that can accidently happen) but the LBS took care of that too with no problems with the cage taking up the chain.
So, I tried it myslelf over the weekend on a 105-equipped bike with a 9-spd triple dr and hoped it would work as well for me with the 105 as the LBS did with the Ultegra dr years ago. As expected, the setup needed more chain. Even so, things still were not quite right with the B-screw stopped down all the way. However, shortening the cable housing at the dr did the trick.