My Benelli M1S90 is currently in factory configuration, except for an extended bolt handle and oversize safety. I am using the VTAC wide padded sling for my AR15 with heavy duty quick detach swivels front and back. Is there any way to mount/install flush cups on the Benelli M1S90? If not, then what options (either slings and/or mounts) would you recommend for this shotgun?