I don't really have an answer to your questions, sorry.
But, I've also been looking for a grain-free food that's lower in protein. This one was recommended to me this week and I like the looks of it (protein is only 26%-27%, and the fat is only 17%). I have not tried it yet to be able to recommend it, but I thought it might be something for you to look into. I'm going to go pick up a bag to try next week.
NOW! Grain Free Pet Food
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