Typically a second stud is located about 2" behind the first. You're free to put it where you want. Do you use your sling for support when shooting or just for carry?
You could also put a spigot bipod mount at the end of the stock and use the existing swivel for your sling ike the bipod mount used by Accuracy International. The lower center of gravity gives the rifle less tendency to fall over on it's side. AI stocks come with the bipod fitting.
I've converted McMillan stocks to use that mount. Never tried a Bell & Carlson.