I went for a walk with the junior assistant. I brought two cameras, the Shackman and the hacked old Kodak.
I have cleaned the inside and have managed to tighten the viewfinder so it doesn’t wiggle as much.
It didn’t really help, still a lot of scratches and leaning horizons. I read that some Holga shooters line the film gate with electrical tape to get a smooth surface, I might try that next. And maybe bring a level for the camera.