I purchased this ambi holster off amazon a few years ago for use with my scoped 7.5 inch BFR's. Simple and works for me.

https://www.amazon.com/Federal-Scope-Sho...s%2C852&sr=8-85

For my none scoped Ruger SBH 7.5 inch I use the Guides Choice from Diamond D Leather, mine is left hand. Very nice rig!

https://www.diamonddcustomleather.com/products/guides-choice-chest-holster