50% is too much protein on a ZC diet. I've read that in the absence of carbs, protein starvation can occur when you exceed 40% protein. I think lean ground beef tends to be 40% protein, so even that is too lean.
Instead of using ground beef to make fatty jerky, I make standard lean jerky, but dip the jerky into fat (tallow in my case), or eat a gob of fat and then a piece of jerky, or eat several gobs of fat followed by a bunch of jerky.
Since raw is advocated here, I'm trying to move toward eating more of my fat, like suet, raw. One thing I've tried recently that I like is melting some suet in a pan at as low a temp as I can, and then dribbling that fat onto a portion of ground grassfed beef. It tastes great, kind of like a meat donut. As a matter of fact, it probably tastes TOO good and too much like a donut, because things that taste like that tend to be bad for us--which suggests to me that raw is best.