I'm glad you bumped this back up!
We switched from Orijen Adult to TOTW Sierra Mountain (our non-Yorkie could not tolerate Orijen after the formula change). We switched probably two months ago, and we are loving it! It's the first TOTW formula we have tried. The biggest difference I noticed was a reduction in eye tearing - a totally unintended consequence, but I do appreciate it.
I did up their food amount, but only slightly. Levi was usually eating 1/8 cup 2 times a day on Orijen. He's now eating 1/4 cup in the morning and 1/8 cup in the evening and his weight has been steady. He weighs a little over 5 pounds.