Turning Fat Cats into not-so-fat-cats-anymore

I get the lecture every single time I go to the vet's office: my kitties need to lose weight. I know this, and I do try, but in a multi-cat home, it's hard to monitor how much everyone is eating individually. Tiger's weight, at his largest, was 22 pounds. He's now down to 16 (which is still big, but significantly more slender). I was forced to be diligent with his weight after he was diagnosed with diabetes (which we found out when he went into diabetic shock, laying in a puddle of his own urine and almost comatose two summers ago), as well as the early stages of kidney failure due to his diabetes.

Besides the obvious buy weight control food option, here's what I did:

1. Smaller cat bowls. Just like when we make a meal for ourselves, humans have the urge to fill the plate completely. Smaller plate = smaller meal. So I applied this to the kitties. Being as I have 4, I went out and bought them colour coded bowls - the tiniest bowls I could find (they're actually itsy bitsy glass ashtrays), and feed them about 10 pieces at a time, but numerous times per day (4-5 times). I feed them larger amounts before bed so that I can get a good night's rest without hearing Cody's desperate "I'm starving!" wails at 3:40am. When you feed them less more often, you're actually tricking them into thinking that they are getting more food. And, isn't that the ultimate goal of domesticated cats everywhere?