Nice reproduction. Can you show us the technique for stitching with the brain tanned lacing?
I used rawhide lacing on this. I cut a strip as long as possible from a piece of rawhide, maybe about 3/16”. I put that in a bucket of warm water to soak and get pliable. I use an awl or a leather punch for the holes spaces around 1/4” apart. Once the rawhide is fairly wet and pliable I take it and stretch and pull from end to end to get it around that 1/8” thickness or so. I then just stitch it like you would anything else and then once you get to the other end I like to start back the other direction and get stitching to fill in the opposite side. Let it dry and it will have some shrink and you’re good to go. Only on rawhide cases do I stitch with rawhide