I want to feed my cats different varieties of flavors - even though trying to use the same brand. Various books and web sites recommend mixing one food with another gradually, replacing 25%, 50%, 75%, then 100% etc. over a one week period. I think this way all the food taste the same, and really kind of odd when you mix tuna and beef. My picky cats don't like this much, although staying with one flavor all the time gets boring after a while, even for a cat. What would you advise?