That 11,9 your quoting is likely a brochures dry weight, which is useless. To understand weights you need to search past posts here. There are hundreds of pages worth of reading.
But to answer your question you need to know
A, weight of your truck loaded ready to travel,
B, pin weight of the proposed trailer based on its GVWR.
C, available payload of your truck which is GVWR minus A.
Since you will never ever tow a trailer dry, use the trailers GVWR. This while giving you worse case, as long as you base stuff on that you will know your safe. Dont forget to add 150 pounds for a standard hitch or 250 pounds if you go with a slider hitch to your teucks scaled weight.
Your going to get lots of people telling you to forget GVWR and go by your trucks rear axle weight, but that is only giving you one aspect of your truck. Others will claim 2500 and 3500s are the same. Others will claim other stuff. Ultimately it is up to you to decide what is safe for your family, who to believe, the trucks mfg or anominous pundunts from an internet forum.
