I want to add sling swivels to my Simson side by side shotgun.

On a shotgun they're usually permanent. Quick detachable studs might look off? An exception is the large hole old fashioned studs like on my Jeffery dr. Hooks are on the sling.

I want to have a sling. This shotgun is carried for tens of kilometres walking on drives. But a sling is not ideal for wing shooting.

Any suggestions?