That is total BS and old fashioned. Nutrition is the key, not what package it comes in.
Rodents have proven a billion times over to be one of the best single sources of nutrition with colubrid snakes.
As mentioned here OVER AND OVER, the ability to utilize nutrition is totally dependant on conditions. In nature, snakes can utilize any temp they need. As its ALWAYS hotter and cooler then there actual requirements.
No offense, About Tom C, I really like him and consider him a friend, but he was never known as a inovative keeper by his peers. That is, if he lived in the north or any place other then S. Fla. he would not breed anything. He is smart enough to stay living where the local enviornment does the work.
So using Tom as a teacher is not such a good thing. Again, I think the world of him(in some ways, not so much in others)
You should understand, the method you keep them is not the base, Fat snakes is based on metabolism, not intake, unless your feeding them donuts.
In nature there are bulky snakes and thin snakes and everywhere in between. But as someone who watches wild snakes reproduce(observe breeding colonies) Its the bulky or Fat individuals with the most consistant success.
The problem is, you cannot compare wild "Fat" snakes to most captive fat snakes. In nature, they have the right temps when needed. In captivity, thats not so. In the vast majority of the cases, overweight snakes are based on not getting the right temps and not diet.