Okay, a long overdue follow up... I tried and was not successful at least not to my satisfaction setting up a Tiagra FD and XT crankset. After much fuss and a lackluster performance I scrapped the idea and moved to a 105 triple and derailleur in the front. I think I had the whole setup up an running in less than an hour including removal of the XT and installation of the 105 crank. I have to say that I'm pretty happy with the 105 it shifts silky smooth and the 50T is growing on me almost as much as the 22T granny. My next attempt will be to try a 26T inner chain ring as the 30 is still a little high for my liking.