Just to follow up on the question I previously asked....
I don't have the Railmaster anymore but have replaced it with a Seamaster! I also bought the strap, which was easy to fit but doesn't quite fit snugly against the case. As a result it is able to rotate a little downwards and leaves a small visable gap between the strap and case.
This is easily rectified however. I simply cut a small piece of leather from the keeper of an old leather strap I have and placed it between the strap and case where the arrow is below. This results in a tight fit and no movement of the strap end. Result!
Click to expand...