Great combo with plenty of towing power and hauling capacity with those 6500 RAWR.
I have a older '03 2500 Quad cab Dodge/Cummins HO NV5600 manual tranny 3.73 gears..9000 GVWR with smaller 6000 RAWR. My 32' 5er weighs 11200-11600 lbs depending on length of trip and how the combo is loaded. My trucks rear axle loads runs in the 5200-5500 lbs once its all loaded and road ready. Front axle loads (empty or loaded) won't change much if any
I wouldn't do a thing to the truck till you load it all up and make a trip. While your out, drop by a set of CAT scales and weigh your trucks front and rear axle loads.
Its rare tires on the newer trucks are the weak link. Our older trucks that used 16" LT E at 3042 lbs capacity were generally the weak link. Today its usually wheels or rear spring pack.
Your gonna' love the towing performance from that combo....enjoy.