What RD is on the Ultimate? If it's Ultegra Di2 GS, it will do 34t. Other Shimano RDs might officially support fewer max teeth, but can usually fit 2-4 more than spec.
You would be losing weight on the bike, so 36-34 front/rear wouldn't be too much worse than what you have. Of course if you don't mind the cost of smaller chainrings, then that's always an option.