I have a FN SXS that is a twin to yours, with the exception that it doesn't have a cheek piece. It's a 16 gauge with 30" barrels, that weighs 5lbs. 14 oz.
It has had barrel work by a previous owner (chambers and chokes)
it is a terrific bird gun despite its long barrels.
I tried to post pictures of it following the instructions.
How do you post multiple images?
Pete