I have been studying about Sholder Holsters for my '58 Remmie 5 1/2" also my Ruger Vaquero. I bought a nice one from RIver Junction Trade Co. a while back and so far it's the only Sholder Holster I have located that dosen't have an across the Chest strap! This kinda makes the wearing of the holster sorta stealth.
This holster has aq thin adjustable strap that goes across the right sholder.
Nice thing is that the Remington and the Vaquero are just about the same length and the cylinders are just about the same diameter so the revolvers can use this holster interchangeably.
I know that a Sholder Rig is slower than a Belt rig on the draw but the convenience ofhaving the revolver completelly out of the way has it's benifits. ie when handling long arms there is no hammer to mar the stockwork of someone elses rifle.