Orient Express - Cheap Chinese Rims / Wheels / Forks / Frames / Cranks / Etc

could never get mine to stay in the designated angle

I think a lot of issues with cylindrical friction inclination adjusters like these are down to where your gravity load passes relative to the cylinder axis. The more off axis you are (e.g. sitting on the nose of the saddle, with the saddle pushed forward in the clamp), the more friction the clamp needs to generate to resist the resulting torque.