I had this problem with Addie, our local rescue groups received a lot of food from us!
Mine have been eating Halo's Spots Stew for a long time, I used the sticky on this forum to calculate the food and it's A+. Also, I found the water, food, microwave thing to not be as successful as mixing some puppy wet food with the dry.
We free fed when Addie and Mia were puppies and we continue to do so. As long as you know the cat isn't eating the puppy food, measure out a certain amount of food and the same time the next morning, pour what's left into the measuring cup. This way you can tell how much was eaten throughout the day. Until I started doing this, the only indication they were eating was their poop.
Don't feed stuff like Beneful. It's like feeding McDonald's to your children every day of their lives. I personally don't like Iams either.
Also, I don't do the timed feeding if your yorkie doesn't eat because when I did this, Addie refused to eat and she had a hypoglycemic incident. That was so incredibly scary, I refused to take the recommendation from my vet that they have feeding times. None of mine gobble the food, they eat a bit here and there, and I've had no problems with them becoming overweight.