I don't know if there's a "right" way, but I can tell you what I've done.
As soon as I found out that the Hill's I got from the vet was bad and found Binky's list and got my refund from the vet I went to the store with list in hand.
Prior to diabetes, I bought mostly 9-lives canned, and store brand dry. I was hoping to stick with 9-lives because I knew my cats loved them. But I had a hard time finding low carb varieties that weren't tuna or another type of seafood and I knew those weren't good to feed every day.
I ended up going to Petsmart (again with list in hand).
I decided to give Bob (sugarcat) nothing but Fancy Feast Classics, and I bought two of every flavor of the classics.
I decided that at that price, I could give my civvie, Mullet, Friskees Pates instead since it would be a little cheaper and the cans were bigger. My other thought was that if I determined that Bob needed more than 2 cans of FF a day, I could feed him a little of the pates out of Mullet's stash to tide him over without causing any big "carb" problems for Bob. I also bought two cans of Friskees pates of every flavor they had.
So that pretty much shot my grocery budget that payday! :lol:
Oh, one week I tried a couple cans of Blue Wilderness? when they came out with new "venison" and "duck" flavors. Neither cat would eat them. Good, because they were pretty pricey.
My goal was to try every flavor and see what each kitty liked the best or wouldn't eat at all.
I got extremely lucky with that. It turned out that both cats ate every flavor. I haven't had one "failure" as far as that goes.
So now it's easy. I go to the store that has either brand on sale that week, stock up on whatever flavors they have, buy enough to get them both through 2-3 weeks, and just give them a different flavor every meal.
So far, no problems with appetite with either cat. And none of the food of either brand has caused Bob to come out of remission. I also try to limit each kitty to no more than 4 meals a week of seafood.
I really hope it's that easy for you too, Amy. I have seen lots of people say that when they switched to a specific brand or flavor, the kitty got either diarrhea or constipated. I haven't had either cat suffer from either condition. Very lucky there too it seems.
Carl